Home » Uncategories » What Causes Ford 8.8 Limited Slip Spider Gears Pitted UPDATED

What Causes Ford 8.8 Limited Slip Spider Gears Pitted UPDATED

What Causes Ford 8.8 Limited Slip Spider Gears Pitted

The main reason to have a limited skid differential in your rear beam is to maximize traction on slippery surfaces, such as snow, ice, or mud, which can be exacerbated with an open differential. Another important reason is to help distribute the torque to the wheels from a high-performance engine and transmission combination. The limited-slip differential transfers torque to both wheels even if one bike is spinning. This is a huge improvement over the traction-limited open differential. Express slip differentials also maximize acceleration of the vehicle.

This Tech Tip is From the Full Book, HIGH-PERFORMANCE DIFFERENTIALS, AXLES, AND DRIVELINES. For a comprehensive guide on this entire subject you lot can visit this link:

LEARN More Most THIS BOOK HERE

SHARE THIS ARTICLE: Please feel gratuitous to share this commodity on Facebook, in Forums, or with any Clubs you participate in. You tin re-create and paste this link to share: https://musclecardiy.com/performance/how-to-rebuild-mill-limited-slip-differentials/

Determining Limited-Slip vs. Open Differential

To make up one's mind whether your vehicle has a limited-skid or an open differential is one of the easiest driveline checks. The offset step is to place the vehicle on a flat and level surface, block the forepart wheels, and enhance the rear wheels off the basis with a jack. As always, practice safety first and place the vehicle on jack stands. Shift the transmission into neutral and make certain that the parking brake is released. Now simply rotate 1 rear bike in the forward direction and pay attending to the rotation direction of the other cycle.

If information technology rotates in the same direction (forward), the rear finish has a limited-sideslip differential. If the other wheel rotates in the reverse direction, then the rear cease has an open differential. It is that unproblematic.

All the same, there is one exception: An extremely worn clutch-plate-mode limited-slip differential may act like an open differential because the plates are so severely worn. So information technology'south non a totally foolproof test. Merely this method works for most cases.

You lot may wonder why 1 wheel rotates in the opposite direction. There is a lengthy engineering reason for this, simply it can be summed up past the following simple equation:

two ten N_carrier = N_left + N_right

Where:

Due north_carrier = rotational speed of the differential carrier

N_left= speed of the left side gear, which rotates at the same speed equally the left tire

N right = speed of the right side gear (or right tire)

If the carrier speed is zero, which basically means that the pinion and prop shaft are non rotating, the left side of the equation is equal to zero.

You rotate one side; let's say the left, at 10 revolutions per minute. In social club for this equation to work, the other wheel, in this instance the correct, must rotate at the aforementioned speed simply in the opposite management:

2 ten 0 = 10 + (-10)

0 = x – x

0 = 0

The equation is satisfied. Basically the differential gears are complimentary to rotate relative to i another inside the differential case while the differential case is stationary.

If a express sideslip differential is in the vehicle's rear beam, a preload should exist applied betwixt the side gears, which would crusade both gears to rotate in the same direction (until the torque generated by the friction of the preload has been overcome). One of two things can happen. The clutch plates can slip relative to the differential, and the differential case would not rotate. If the differential example does not rotate, the hypoid ring gear and the pinion will not rotate. Basically, it would be the path of least resistance. Hopefully, the ring and pinion rotation torque is lower than the torque to slip the clutches, and therefore, the pinion rotates.

If this sounds confusing, don't worry. This is a little difficult to sympathise and is only meant as additional information. The most important thing is to understand how to test for the presence of an open or limited-slip differential.

With the bike adapter tool you can rotate the torque wrench at the centerline of the axle shaft. You lot merely demand the right bolt blueprint and nut welded in the center. This domicile-fabricated tool is round and spans all five lug studs; a triangle-shaped plate that spans 3 of the studs works fine also.

The limited-slip checking tool just fits over the wheel studs. You just need to terminate the other bicycle from rotating.

With the tool in place and the torque wrench in identify, you lot can rotate the tool and tighten the bolt. You just demand to read the torque values for break-away and slipping torque.

Once you accept determined that you have a limited-slip differential, y'all can check the preload or interruption-away torque relatively hands. You volition need to fabricate an adapter to permit your torque wrench to line upwardly with the center of the cycle bolt pat-tern. This homemade tool can exist every bit simple as a steel plate with the bolt pattern drilled in, and a large nut welded in the center that is aligned with the centre of the axle shaft.

At present stop one wheel from rotating (such as jacking only one tire off the ground), remove the other wheel, and put the adapter over the lug studs. Make sure that the parking brake is non applied; you don't want to exist fighting the brakes at this stage. At present just put your torque wrench on the large nut in the eye of the adapter and take a reading of the torque earlier the axle begins rotating. This tin be accomplished with either a axle-style or click-blazon torque wrench. If you use the beam mode, information technology is helpful to have an banana read the numbers. If you use the click type, set up a torque of 100 ft-lbs initially. If the axle does not rotate, keep increasing the torque until it breaks abroad.

Typically, if the breakaway torque value is below 50 ft-lbs, the differential needs to be rebuilt or but re-shimmed. A skilful range for street use that still provides decent performance is betwixt 110 and 140 ft-lbs of torque. If the clutch pack is shimmed tighter, it produces poor on-road manners during slow, tight-turning maneuvers. These poor manners are exhibited by tire wind-upward during a low-speed, tight turn maneuver (such as pulling into a parking spot). Too, the differential volition act more like a locked differential and the vehicle tin tend to under steer or plough.

The above data is true for all traditional factory type-differentials. You should go on in listen that the helical manner differential behaves like an open up unless the torque bias ratio is very loftier.

Tear-Downward Procedure

Every rear terminate has a differential (run into Chapter 1). There are many types bachelor, simply I will concentrate on the most common types, which are the open (or standard) differential and the express-slip differential.

Every manufacturer has its own unique proprietary name for these limited-slip rear ends, but all of differentials essentially function in the aforementioned way. I chose the Ford Traction Lok as an example to rebuild, simply keep in mind that it is very similar to the GM Eaton-style differential and others. These are relatively simple mechanical devices that are quite constructive when compared to an open differential. If your express-slip differential is worn out, you volition end upward laying down i of the most monstrous, single bicycle peels possible.

The first step is to remove the differential from the beam housing (every bit outlined in Chapter 3). Consider removing the ring gear for the rebuild procedure. Some differentials can be rebuilt with the gear yet fastened (depending on gear ratio and manufacturer), just the differential is a fleck heavy and bulky, and the ring gear only adds to that. Additionally, the band gear tin can partially cake the already modest differential case windows. Normally the tear downwards is much easier than the re-assembly process considering in most cases the clutch pack is worn and loose.

Once the differential is removed from the axle and the ring gear is off, the next stride is to remove the differential pin commodities and push the differential pin out. The differential pin commodities is the 5/16-inch head bolt with the long shoulder on it that keeps the differential pivot from falling out.

It is likewise a good idea to supervene upon the bolt, if possible, or at to the lowest degree re-utilise a thread locker earlier last installation.

Next, remove the preload jump. To make it easy, use a hammer and soft punch or suitable piece of woods to tap the jump out.

Exist conscientious as y'all push button the concluding portion of the Ford S-fashion spring out. Information technology tends to follow the differential side gears' tooth path and may shoot out of the housing. To minimize the take chances of the spring flight out, place a rag over the reverse end of the differential case window.

Once the spring has been removed, take notation of how much play there is in the gears. Go along in mind that the thickness of the clutch packs and shims controls the position of the side gears. If the clutches are worn, the side gears are allowed to motility farther outboard and the gears have more backlash or clearance between the teeth. (This is the aforementioned blazon of backlash or clearance that nosotros volition check when setting upwardly the hypoid gears in Affiliate 6.) A typical adequate backlash range is 0.005 to 0.015 inch.

Since we are talking about high-functioning rear axles, you should shim the pack tighter for your hot rod and driving preference

Before you remove the internal gears and clutch pack, marker and go on track of the side gears so they can exist returned to the same position or purposely swapped if excessive clothing is visible. This is not absolutely necessary, merely you desire to make certain that you continue runway of the parts and have plenty of bench space to lay out the parts.

Equally you inspect the gears for vesture, don't fault machining marks for wear. Revacycle is an older machining process for producing the tooth contour, and information technology produces machining marks from the within bore of the tooth confront to the outside diameter. This process is even so used today but is not very common.

The differential pin retention commodities threads into the differential instance to concur the pin in place.

The differential pin retentiveness bolt threads into the differential case to hold the pin in place.

Drive out the Ford-style S-jump between the side gears and through the differential window. The jump will pop out the reverse side. As it is under some compression, be certain no ane is standing in front of it when information technology finally releases.

In order to prevent the spring from shooting across the shop, a rag is placed over the end of the differential case to catch the spring. This sounds like common sense, but many folks forget it and the spring flies across the store. More importantly, you lot don't want to risk injury.

With the gears in identify with the clutch, nosotros can cheque the backlash with a dial indicator.

The Revacycle gear is a cut gear as opposed to a net-forged gear. There are serrations from the cut process on the gear molar surfaces and at that place is no webbing on the inside or exterior of the gear.

A net-forged side gear has a much smoother molar surface. Since the tooth contour is forged in place and not cutting, it allows for webbing to increase the force.

But like old bearing races, these can exist helpful as printing tools. One-time beam shafts can be used to help rotate the side gears. Hither we cut the shaft down in length and welded a plate to the end.

We can also use a complete axle shaft; we just need an erstwhile bicycle to commodities to it. This takes up more space in the shop, only is easier if y'all do not have access to a welder.

The differential pinions accept spherical washers on the ends. These washers are very important to assist with wear, and then be careful not to misplace them.

Once we are prepare to rotate the differential housing, nosotros tin use the differential pivot for this purpose. We partially install the pivot and rotate the housing to walk the gears out.

Once the pinions are out of the differential, the side gears can be removed likewise. Carefully remove the clutch pack and shims with each side gear. Note that the last shim tends to stick in the housing, from the lube moving picture.

Using either net-formed or forged-tooth profiles is a more electric current process, and this process does not have signs of machining on the gear teeth. The net-formed process is becoming the standard for all new differential gears. The process allows for additional webbing in the gear profiles and therefore stronger gears.

The differential pinion gears (a.k.a. spider gears) can exist rotated out. There are a few methods to do this. If the clutch pack is worn, information technology can be as easy every bit simply rotating the side gears, and the pinion gears will plow relative to the side gears inside the differential case and "walk" toward the window.

If the arroyo of rotating the gears with your fingers doesn't work, at that place are tools available to assist do this. In fact, you can make your own tool. An onetime beam shaft, with the spline end cutting off and a foursquare plate welded to information technology, is a practiced makeshift tool.

Another way to achieve this (if you don't have an beam shaft that you are willing to destroy) is to place the axle shaft from the vehicle vertically in a bench vise and place the differential over the splined stop. Yous can even take the original axle shaft and bolt it to the wheel. Then just set the wheel on the ground with the axle pointing vertically upward.

At present that the differential side gear is essentially locked to the bench vise via the splined connectedness, rotate the differential case. The pinion gears volition walk around inside the differential case, assuasive you to remove them from the admission window. In addition, pinion thrust washers are typically located between the pinion gears and the housings and usually these come right out with the gears. If y'all don't see them immediately, look closely, as they may be stuck to the pinions or inside the differential housing from the lube motion-picture show.

If, for some reason, the differential example won't rotate past mitt, do non worry. Some of these can be very tight. I recommend partially installing the differential pivot into the differential case. Install information technology just plenty to engage the housing, only non the within diameter of the pinion gear.

The pinion gear needs to exist free to rotate relative to the case, and the pin restricts that if inserted as well far.

You can put a "cheater bar" on the stop of the differential pin to get additional leverage. Be very careful; the pin is hardened and the case is just cast iron. Never pound or bang the pivot during this process. Evenly pull on the bar until the pinions rotate. If you yank and bang on the differential pivot, at that place is a good chance that the differential pin pigsty will exist damaged.

Once the pinion gears have been removed, the superlative side gear and clutch pack will desire to autumn out of the case because the differential is vertical. Be prepared for this and catch the gear and the clutch pack. Again, note the order of these parts and their condition; you don't want these parts falling and billowy all over the shop. Make certain that the shim between the clutch pack and differential instance has also come out.

At present the other side gear, clutch pack, and shim can exist removed. At this betoken, the differential instance should exist completely empty. This is the perfect time to clean the differential case, either in a parts washer or rinsed thoroughly with brake cleaner.

Checking the Parts for Habiliment

Lay out the gears and clutches on a demote, in the exact order that they came out of the differential. Just retrieve which side went toward the ring gear flange side of the instance and you lot are all set.

In my discussions with the axle and differential experts at Drivetrain Specialists (DTS), they reported observing wear on the side gear teeth. Take a good, long look at the surface of the teeth and look for signs of wearable. The habiliment is usually concentrated on i side of the teeth because the teeth are loaded more severely in the drive direction relative to reverse. If the gears are worn on only i side, you lot can switch them from left to right and that will load the other less-worn side of the teeth in the bulldoze direction. Your other selection is to replace the differential gears.

Take a proficient look at the clutch plates and reaction plates. The tabs on the exterior diameter of the clutch plates hands identify them, and you lot should exist able to run into friction textile bonded to them. Likewise, inspect the differential pinions and the thrust washers. If wear is observed in the thrust washers, cheque the beveled surface between the thrust washers and the differential case for signs of wear or scoring due to a seized thrust washer that has spun in the case. At that place are new thrust washers avail-able, and you should supercede them during your rebuild anyhow.

The reaction plates are the steel plates with the spline on the inside bore. These plates absorb virtually of the heat generated during skid events. This heat is dissipated in the gear oil and the differential case.

1 molar is actually chipped on this excessively worn side gear while the others show significant amounts of pitting and wear.

Here is a typical tabbed-style clutch plate, which happens to accept woven carbon fiber equally the friction material. The carbon-fiber fabric resists clothing and can handle higher temperature when compared to traditional newspaper-based friction.

The reaction plates usually have an internal spline, special coating, and surface finish for proper interface with the friction material. These plates should not be mixed with different friction materials, the surface coating and preparation on a microscopic level has been optimized to work with the mating friction textile.

The Ford 8.8-inch differential gears are actually painted at the manufactory, so they can be easily identified in the manufactory. This side gear has a clutch pack with the latest carbon-friction-fabric-plates installed.

On the left is the typical amount of wear that you will find on the first and second plates. The plate on the correct shows very lilliputian sign of clothing.

Depending on the mileage and usage of the differential, the clutch pack probably shows signs of wear and scoring. Information technology is a prophylactic bet that the unabridged clutch pack should be replaced, especially if the differential, when assembled, had excessive play. This is the best mode to restore proper function to the Traction Lok differential.

This is a great time to upgrade to the carbon friction plates that are used on the 2003 to 2008 SVT Mustangs. This is Ford part number M-4700-C, and this kit comes with a new preload spring.

The Ford stock-type clutch pack rebuild kit is part number Grand-4700-B. For some reason, the carbon mode clutch pack rebuild kit does non include a friction modifier; the stock-style plate kit does include it. A friction modifier is required and needs to be purchased separately for the carbon-fashion pack. Also, both of these packs come with the correct clutch pack height and shims to match the factory specifications.

Typically, the first and second plates vesture the most on whatsoever clutch pack. This is considering, when the separating force from the gears is applied to the clutch pack, the first and second plates start transferring the torque commencement and then the other plates come up into play. If they transfer adequate torque, the other plates encounter less speed difference and subsequently habiliment less. If you lot are going to re-employ your old plates, which I exercise not recommend, yous may desire to move the offset couple of plates to the heart of the clutch pack. This should put the least-worn plates in the first and 2nd position next to the side gear.

Rebuild Process

The assembly procedure is the opposite of the tear-down process, but there are a few special things to watch out for. Depending on the blazon of preload that you desire across the differential, you can shim the clutch packs tighter or looser. The tighter the clutch packs are, the more than windup and potential chatter. You lot can also upgrade the spring to an F-150 jump. The F-150 spring is approximately 1/four-inch wider than the typical passenger car jump. Its free height measures around 1.765 inches, equally compared to the auto spring at 1.510 inches.

But permit's keep in heed that we are building a high-functioning rear cease, non simply a stock rebuild. If you cannot get together the differential by paw, the clutch pack is too tight.

The first step is to soak the friction plates in friction modifier for at least 20 minutes. You can withal expect a few initial "pops" out of the clutch pack when the vehicle is driven. Normally, you lot should but hear virtually a dozen or so. The longer the plates are pre soaked, the less initial popping will be present. Overnight would exist the maximum amount of time before at that place is no additional benefit. There is certainly no need to soak the plates any longer than 12 hours.

Be certain to have a clean, shallow, plastic or steel pan to concur the modifier and plates in. A cookie sheet works great for this, but don't utilise it to bake with afterward. You are only soaking the friction plates. The steel reaction plates do not require this step.

The friction plates demand to exist soaked in the correct friction modifier prior to installation. This soaking process really conditions that friction as the modifier is absorbed into the fibers of the material. Hither we take three of the plates soaking for xxx minutes.

Too, if you are going to use the latest carbon fiber style plates, y'all should properly dispose of the friction modifier used for soaking the plates and only use fresh modifier when y'all fill up the axle.

While the plates are soaking, make sure that you have all of the parts you need and that they are make clean and dry. During the assembly process, lubricate all of the parts before assembling them into the unit, making sure that they aren't dry when y'all starting time outset driving the auto. Therefore, make sure that y'all take some fresh gear oil nearby (the same oil to be used for the final axle make full).

Lay out the clutch pack associates in the right society. You should have a full of three friction (F) plates, iv reaction or steel (R) plates and 1 shim (Due south) per side. The society is as follows: side gear (G), reaction plate, friction plate, reaction plate, reaction plate, friction plate, reaction plate, friction plate and shim (Thousand-R-F-R-R-F-R-F-S).

Some enthusiasts use a different social club and even install boosted clutch plates for a tighter differential. Your strategy depends on your level of expertise and what the vehicle's application (high performance, drag racing, road racing, etc.) is. At that place are even rumors of people grinding the friction plates to get more in the total clutch pack stack.

I similar to stick with the factory order and just shim the pack tight. If y'all are working on an early axle (1980s vintage), notice that the clutch plate tabs are square and the new style has rounded tabs. The square tabs are no longer bachelor. Remember of it as a weight savings and your car will exist that much faster.

Also, the order of the plates has changed over fourth dimension. The club for the 1980s-manner differentials as stock was: side gear, friction plate, reaction plate, reaction plate, friction plate, reaction plate, reaction plate, friction plate, and shim (G-F-R-R-F-R-R-F-S).

Note: An beam of any vintage should exist rebuilt with the updated clutch pack order (G-R-F-R-R-F-R-F-S). If the friction plate is placed directly confronting the side gear confront, a couple of undesirable things happen. Beginning, wear is imparted to the back confront of the gear. 2nd, the clutch friction surface is larger than the mating surface on the dorsum of the gear.

We take bundled the clutch-pack stack and shim so that you can see the proper social club of the steel and friction plates. It is important to go the order correct to achieve the right functioning. This stack requires a 0.020-inch shim.

Close examination of this gear and pack assembly reveal that the clutch plate actually is larger than the gear. The clutch plate hangs over slightly past the gear.

This smaller surface area results in a pres-sure increase on the clutch face up and more wear occurs on the gear and plate. Some people fifty-fifty try adding more friction plates to the pack. This does permit for more friction surfaces and additional torque chapters in theory. The problem is that the one clutch surface has to run on the back of the gear surface. My opinion is to avoid this birthday and stick with the latest recommended club of plates (G-R-F-R-R-F-R-F-South).

It is as well very helpful to add gear oil to each plate during the assembly process. This makes it easier for the pack to stay together and again alleviates any dry out running concerns.

On the assembled clutch, discover the two reaction plates next to one another in the 3rd and fourth position. The chief reason for this odd order is to provide a good heat sink to assist out the first clutch plate and to allow for full face contact. Each assembled clutch pack consists of vii plates and the appropriate shim.

Now is the perfect time to align all of the friction plate tabs. This will make it easier to drib the assembly into the differential instance. These tabs fit into the pockets in the differential housing. Once y'all accept one complete side gear assembled with the clutch pack and shim, information technology tin can be loaded into the differential housing. Double check that the clutch plate tabs are all located in the windows in the differential housing.

A piffling trick here to see how tight the pack is without completely assembling the unit is to install the 2 pinions and cross pin without the other side gear. Insert a screw-driver between the differential pin and the confront of the installed side gear and lightly pry to simulate the employ force of the preload bound. With the forcefulness applied, carefully rock a pinion back and along to bank check backfire. If yous have no back-lash, the pack is too tight. If the backfire is much across 0.020 inch, the clutch pack is too loose.

These are all of the internal components of a limited-slip differential. We have arranged them outside of the differential to testify the relationship of the parts. One time installed in the differential instance, it can be difficult to run into all of the components.

The clutch plate tabs must marshal with cutouts in the differential casting. This semi-circular notch tin can be seen nearly the bottom of the access window.

It may be tricky to get gear up with a dial indicator without an assistant. Yous can wait until the entire differential is congenital without the pre-load leap installed and check it again. Of grade, if you want a real tight differential, you need to shim it tight. A good range for back-lash is 0.001 to 0.006 inch.

Yous can purchase consummate clutch packs that are already shimmed and ready to become. If you go that road, be sure to keep everything together every bit packaged. Be careful not to mix things up while the friction plates are soaked in modifier. This is a quick and easy mode to go because you can skip the whole clutch pack shimming and backlash setup.

You can measure the clutch pack assembled height in advance to get an thought of how close y'all are. The Ford style'due south typical range is 0.640 to 0.645 inch. The performance kits can be as thick every bit 0.655 inch. The easiest method to mensurate the pack is to lightly clench the pack with a C-manner clamp and measure the overall thickness with a fix of calipers or a micrometer. It is likewise recommended that the clamp thickness of the left and right packs is kept shut to ane another. If there is too much variation, it can exist difficult to install the differential pin afterwards in the associates procedure.

Once again, if the pack is too tight, the pinion gears are extremely difficult, if not impossible, to get together. Also, keep in mind that you want backlash or clearance in the differential gears when they are completely assembled.

As stated higher up, this comes downwardly to personal preference. If you are planning on running slicks and racing often, shim information technology tight. The differential is shimmed too tight if you cannot get it put together. The tighter the pack the more windup or bind you lot will notice during low-speed, tight-plough maneuvers such equally pulling into a parking spot.

This preload that is being congenital into the unit and the forcefulness provided by the S-spring is all static preload. Once the differential gears (not hypoid) begin rotating relative to one another, the separating forces from the gears apply additional thrust loads to the clutch pack to resist this spinning. As mentioned earlier, this is the speed deviation as compared to between the left and right wheels, and not vehicle speed.

The chart shows speed deviation plotted on the horizontal centrality against torque transferred on the vertical axis. You can run across that the line does not begin at the nix betoken, where in that location is no speed deviation across the differential gears. It is actually kickoff up on the torque curve. This corporeality of offset is based on how tight the pack is assembled and the force applied past the S-spring.

There are many "former tricks" that work, only aren't always the best idea. Some folks build the clutch pack tight and omit the S-leap. This allows the pre-load to be zero and the differential will allow speed difference under light torque easily, just like an open up differential. And so, when higher torque is applied, the separating forces from the side gears further shrink the clutch packs. In this state of affairs, if one wheel begins spinning on a slippery surface (ice, gravel, etc.), the torque is very low in the organisation equally the resistance between the tire and the slippery surface is very low. Stepping on the gas pedal harder does non produce more torque in this case. The S-leap helps in this specific driving condition. If y'all are concerned about too much preload, don't substitute the stock spring with a stiffer spring.

In order to mensurate the overall pack thickness, nosotros lightly clench it together and measure it with a micrometer. In this case, nosotros used a pair of vernier calipers to measure the overall pack thickness or height.

The Ford service kit comes completely assembled and pre-shimmed. Although this takes the shim adjustment part out of the equation, nosotros still need to detach the clutch pack in order to soak the plates in friction modifier.

This graph represents a typical preloaded clutch-pack-way limited-slip differential. The clutch-pack preload shifts the graph vertically so this is no speed difference beyond the differential, simply there is still a resistance to differentiation from the preloaded clutch pack. Once a speed departure occurs, the side gear separating loads applies additional forces to the clutch pack.

The nut and commodities with big washers provide an assembly help. While typically non required, it can be helpful. In one case the pinions are installed, y'all tin can remove this nut, bolt, and washer arrangement.

Although pinion washers can be difficult to re-install in the differential, brand certain to go them in place during the assembly process.

It is possible to rotate the pinions in place by yourself, simply it's much easier to accept a second person aid. Observe that the pinion washer is correctly in identify.

Every bit long equally the pinions are lined upwardly correctly, the differential pin will slide smoothly in place. It is all-time to check this alignment at present before the ring gear is installed.

It is very piece of cake to install a pinion one tooth off. When this happens, it is impossible to correctly line upwardly both pinions through bores with the differential case. If this situation occurs, y'all need to remove the pinions and beginning over.

If yous take temporarily installed the pinions and differential cross pin, they need to be removed. Now you can install the other side gear with clutch pack and shim. Double-check that you have the clutch pack order right. This is where things get tricky. Yous need to agree the side gears in place while putting the pinions in place and getting all the teeth to line upward. Yous tin can utilize a commodities with large washers to temporarily hold the side gear(southward) in place. Y'all can get by with-out this assistance, merely it can exist helpful.

Exercise not forget the spherical pivot-ion washers that go betwixt the pinion gears and the differential case. Accept your time and be patient; these can be catchy to install. At this stage, assist from a 2nd per son can be helpful, although it is not required.

In one case the pinions are in identify, y'all need to rotate one side gear relative to the differential case to become the pinions to rotate into place.

If the gears are all lined upwards correctly, the differential cross pin should drop right in.

If the pinion teeth are off by one and yes, it is possible one pinion hole may line up correctly, but the other may not.

Unfortunately, in social club to correct this misalignment y'all need to rotate the pinions back out and index i pinion over to the adjacent side gear molar. This is where the bootleg splined axle shaft tool is so helpful. Once again, exist patient and become it right.

Once the gears are in, installing the S-shaped pre-load spring is the last stride. There are many ways to do it. You lot can shrink the bound in a vise or utilise plates on either side with a C-style clench, or simply tap it in. I have done several of these and am comfortable with merely tapping them in with a hammer. Be careful, this is made out of hardened bound steel, and you don't want to cleft or over-shrink information technology.

Side by side, I similar to put the differential pivot in place and start the cantankerous pin bolt a couple of threads. This ensures that everything stays together until I am set up to put it dorsum in the car. A trick to help align the cantankerous pin bolt is to put the bolt in the pivot before pushing the pin in all the style. Then, apply the commodities as a handle to turn the pin and marshal the bolt with the pigsty in the differential case.

The concluding stride is to remove the commodities, button the pivot in flush, and the bolt hole should line upward perfectly.

Final Assembly and Operation

When you get the axle completely re-assembled, don't forget to add the correct corporeality typically iv ounces of friction modifier to the lube fill. This is very important to make sure that the clutch remains quiet over time. Y'all should plan on using traditional non-constructed gear oil during burglary. After you have 500 miles or so on the gear, feel complimentary to alter the oil and switch to constructed if you similar.

If yous take replaced the ring and pinion set, check to see if the manufacturer has added a phosphate coating to the pinion and/or ring gear to help the gears break in properly. Think of this similar apartment tappet camshaft break-in lube that is added during engine assembly. E'er follow the instructions that came with your new gears or differential if they vary from the information higher up. Some gear and clutch manufacturers recommend constructed lube during the break-in procedure.

The preload S-spring can be com-pressed with channel-lock-style pliers or a C-clamp to assist with installation. Once you have rebuilt several of these units, yous develop the experience for how much to tap the spring to get it started in place.

Orient the differential pin retention pigsty before the pin is completely installed. Nosotros like to employ the retentivity commodities to help us visually orient the pin before we push it in all the way.

In one case the pin has been completely installed, you should put the retention commodities in identify and lightly start the threads. This will make sure that the pin does not fall out before you are ready to install the differential.

At present that the Traction Lok is rebuilt and installed, yous should no longer take that embarrassing single wheel peel. You can confidently put downwards two black ribbons of tire rubber. Of course, before you endeavour this, brand sure that the hypoid gears are properly broken in (if they were replaced at the same fourth dimension as the differential rebuild).

The typical amount of time required to perform the rebuild is iv to v hours depending on your skills and how many you take done before. It is not a difficult task, even for the beginner. Information technology just takes time and patience.

GM-Fashion Limited-Slip Differential

The GM-style limited-skid differential doesn't apply the Due south-way spring for preload. It instead uses a series of wound-ringlet springs trapped between two steel plates. Eaton Corporation produced these differentials, which are typically referred to as Positraction rear ends. The Eaton Posi was first introduced as optional equipment in 1960s-vintage Chevrolet rear axles.

The Traction Lok assembly and disassembly instructions utilize except for a few minor changes relative to removing and installing the springs and plates. Basically you follow the same steps until information technology is fourth dimension to remove the South-spring. So you tap the spring pack partway out through the differential housing window with a contumely punch (not all the mode, as you want the pack to remain intact and not wing apart). Commonly 1 inch or so will do.

Many people swear by the Blueish Oval make of friction modifier. The modifier is available in four-ounce bottles from any Ford dealer.

With the proper preload beyond the differential and a proficient set up of clutch plates, the rear axle acts like a spool during hard acceleration. This is axiomatic considering both wheels have left a black patch during a burnout, and those patches beginning at the same time. If ane patch starts before the other, it may be a sign that the preload is not high enough.

The GM-style limited-slip differentials use four compression springs equally opposed to the single S-style spring Ford uses. Eaton builds these differentials both as factory-installed and aftermarket units.

The spring pack needs to be tapped out like the Ford Due south-spring. Yous want to make certain that you alternating between the spring plates and exercise not hit the springs themselves.

Once the spring plates are partially pushed out, you can take hold of them with a suitable set of pliers. Just compress the springs, and the plates and springs should pull out.

The 200-, 400-, and 800-pound spring and spring plates are shown from left to correct. The jump plates become thicker as the spring rate increases. Also, the spring wire diameter and number of active coils vary and, consequently, it is piece of cake to visually tell which springs have been installed in the differential.

Side by side grab the spring pack from the opposite side window of the differential housing. Use a pair of locking pliers and remove the unabridged pack.

Inspect the plates and springs for cracks; clean and supplant as required. If yous desire a higher preload torque, at present is the time to replace the leap pack with a stronger ready. Typically for these units, at that place are three jump-preload options available: 800-, 400, or 200-pound. The higher the bound force, the college the preload and torque bias ratio.

Spring Force Math

In that location are rumors out there suggesting that the advertised force from these springs is not correct. I decided to perform some contrary engineering to verify which is true:

yard = Yard 10 d^iv/ (8 x Due north_a 10 D³)

Where:

k = spring rate expressed in lbs/in Chiliad = shear modulus of elasticity (a abiding value of 11,312,516 psi for steel)

d = wire bore in inches

Due north_a = number of agile coils. The term active coils or a turn of a pinch leap refers to the number of turns of the wire material that actually deform during pinch. Most springs are designed to have the top and bottom coils ground flat to allow for better seating. The ground section of the spring is not considered active in this case.

D = mean coil bore in inches, which as well can be found as (inner diameter + outer diameter) ÷ two

One time we accept the spring abiding calculated, we can observe the force per spring by solving the following equation:

F = 1000 (Δx)

Where:

Δx = (spring free pinnacle) – (spring installed height)

We made some estimates for the number of active coils and rounded to the nearest number. We likewise considered the different spring plate thicknesses and came up with the following:

From this we get the spring rates (k) as eighty, 364, and one,485 lbs per inch, respectively.

Now we assume that the full compressed height is 1.32 inches and take into business relationship the two spring-plate thicknesses. We used the in a higher place force equation with the following parameters:

This yields forces of 45, xc, and 163 pounds, respectively. Since there are four springs in parallel, nosotros multiply the forces past four to yield 180, 360, and 650 lbs per inch, respectively.

These are very shut to the advertised values, especially when yous consider that we made some approximations for values such as the number of agile coils, compressed height, and wire bore. Go on in mind that you cannot just have the 200-pound numbers and multiply by four to go the 800-pound leap numbers. In that location are differences in plate thicknesses and, therefore, in the compressed heights of the springs.

Differential Gear Removal

Follow the Traction Lok process to remove the rest of the differential gears and plates. Always keep rails of shims and the order of friction plates and steel plates so you can reassemble them in the same club. A new friction plate is approximately 0.070 inch thick for this style differential. As well, this style clutch pack uses small-scale hardened caps, upon which the clutch plates ride within the differential instance. These just preclude the plates from wearing grooves in the instance and inhibit free motion of the clutch pack.

When it is time to re-install the spring pack, you merely need to squeeze the pack together betwixt some plates with a C-style clamp and and then tap them in betwixt the side gears. Once the leap pack is started, yous tin remove the clench and end tapping the pack dwelling house.

As with the Traction Lok procedure higher up, in one case the pack is in, double-check that the differential pin assembles easily without interfering with the spring pack.

The clutch pack tabs run on these hardened caps. There are 2 caps per side-gear-and-clutch combination. Therefore, y'all need to install four caps per differential.

A C-clamp with some steel plates can be very helpful to compress the spring pack. Then we can tap the plates in place. Think, you lot want to tap the plates and not the spring themselves. Make certain that the springs stay aligned on their seats.

The pinch-spring-mode differentials accept different options for preload springs and clutch-plate quantities as well as clutch friction cloth (every bit described in the "GM-Style Limited-Slip Differential" section above). As a consequence, y'all can gear up upwards dissimilar preload torques. The following describes some of the combinations for this type of differential.

If you stick with the typical stock springs that produce a internet force of 200 pounds, you take a couple of choices: The stock steel plates with a nine-plate pack setup per side (fabricated up of 5 friction plates and 4 reaction plates), or a 7-plate pack per side setup with carbon-cobweb friction plates (fabricated up of four friction plates and iii reaction plates). The carbon-fiber plates are a bang-up upgrade over the steel plates and significantly reduce, if not eliminate, clutch chatter. (Remember every bit the preload increases, the trend for chatter increases.)

If you switch to the 400-pound bound setup, y'all can use the vii per side organisation with carbon plates, which is the standard for new Eaton differentials, or you lot can use steel with a nine-plate pack per side similar to a higher place.

If you switch to the 800-pound jump setup, yous can once more choose between a 7-per-side carbon-style pack or a nine per side steel-pack arrangement. Every bit e'er, the steel pack produces a fair amount of clutch plate chatter. The virtually aggressive kit is the 11-plate-per-side organization with steel plates and 400-pound springs, or carbon plates with 800-pound springs. These two arrangements wear extremely quickly and are meant for drag racing only.

Just how much bias torque is theoretically achieved from these different arrangements? The torque capacity of whatsoever clutch tin exist represented by this simple equation:

T = μ 10 Northward x R_m 10 F

Where:

T = torque in ft-lbs

μ = coefficient of friction (a dimensionless number, typically 0.10 for these clutch plates in gear oil)

R_m = hateful diameter of the clutch plate surface in feet (0.2458 human foot for the GM-style plates)

F = utilise load in pounds

N = number of friction surfaces

Here are the results of our calculations:

The bias torque value is a linear relationship to the spring strength. As the leap force doubles for a given clutch pack's total plate count, the bias torque also doubles. (See Chapter 5 for more about clutch pack preload and side gear separating force.)

Keep in listen that the higher the preload torque, the tighter the differential, or the less likely the differential is to unlock and let a speed difference across the wheels. The tighter the clutch pack, the more windup and dissonance can exist expected from the rear axle, especially in deadening, tight-turn maneuvers. Basically, the on-route street manners of the vehicle will be compromised as clutch pack preload increases.

Cone Manner Limited Sideslip Differential

Chrysler Sure-Grip limited-slip differentials are typically constitute in viii^3⁄4-inch rear ends. There were two variations bachelor: the plate blazon (described before) and the cone blazon. Models from 1958 to 1969 used the plate-fashion Dana Ability Lok. Borg Warner originally manufactured the cone blazon from 1969 to 1974. The cone type cannot be rebuilt; your best option is to purchase an aftermarket unit if yours is non working correctly.

The cone-way limited-slip differential has the aforementioned function as the plate-way but uses cone-shaped friction surfaces. If you expect closely at the side gear near the circular window on the left, you tin can see a portion of the cone surface. (Auburn Gear)

The cone-style limited-slip differentials perform the same function every bit the plate style. There are but a couple of differences in design. The cone fashion utilizes a conical-shaped friction surface, much similar a manual transmission synchronizer, and there is typically only a single surface per cone. Borg Warner originally produced them in the 60s and 70s nether the proper name of Spin Resistant. Many of the Big Three vehicles (GM, Ford, Chrysler) used them. In the early 80s, Auburn Gear began manufacturing differentials with the cone-style design and still produces them today. The units have a set of thrust plates with preload springs between them that look similar to the GM preload springs.

The cone-blazon surface reacts against the differential case and they end upwardly existence a matched set. Some enthusiasts mix and lucifer different parts from multiple differentials in an attempt to repair a worn-out unit of measurement. This is not recommended and the performance cannot be predicted. You may become lucky, but information technology is not worth the risk. Fortunately, these units are replaceable. Auburn Gear actually offers a straight commutation pro-gram. You can go to the nearest benefactor and, for the typical price of a clutch pack rebuild kit, you tin can exchange your worn unit for a new differential that's fix to go. A prissy attribute about this programme is any updates or improvements to the parts are already included in the replacement hardware at a reasonable cost.

Ford Mustang Differentials

In that location are several differentials that have been offered for the Ford 8.8-inch axles typically establish in the Mustangs over the years since the introduction of the Fox chassis. I am not going to review all of the older-style (pre-Fox) designs but volition cover virtually of the unlike combinations that take been available for the vii.v-, viii.5-, and 8.8-inch axles.

The offset thing to be aware of is that all of them are ii-pinion differentials.

Remember that all 28-tooth-spline side gear differentials require a iii/4-inch differential pin, while the 31-molar side gear differentials utilize a vii/8-inch-diameter differential pivot.

The 7.5-inch band gear axle has a 28-molar spline and a x ten 16-tooth combination. There are x teeth on the differential pinions and xvi teeth on the side gears. The typical application for this beam is the Five-half dozen Mustang.

Here are the various Ford differential gears that are bachelor. From left to right: seven.5-inch 28-tooth spline 10 x xvi tooth combination (blue), 8.v-inch 28-tooth spline 10 x 16 tooth combination, 8.8-inch 28-tooth spline 10 ten 14 molar combination, eight.eight-inch 31-tooth spline ten x 14 tooth combination, eight.eight-inch 31-tooth spline 9 x 13 molar combination.

The viii.5-inch ring gear beam has a 28-tooth spline and a 10 10 16-tooth combination also. Some applications are the Flim-flam chassis (1979 to 1993) Fairmont, Zephyr, Mustang, Thunderbird, Granada, etc., and Explorer/Ranger.

One eight.viii-inch ring gear axle has a 28-tooth spline and a 10 x 14-tooth combination. This was a hybrid differential. It has an upgraded differential example that is stronger than the previous differential. This is the differential that you want if you lot are not going to upgrade to 31-tooth-spline axles and you broke your 8.v-inch 10 x xvi differential. These are plant on the SN95-chassis (1994 to 2004) higher-powered V-8 applications, such equally the Marauder, Bullitt, and Mach 1.

Another 8.eight-inch ring gear axle has a 31-tooth spline and a 10 x 14-tooth combination. Some applications for the differential are the F150 and S197 (2005 present) V-8 Mustangs.

The third viii.eight-inch ring gear axle has a 31-tooth spline and a 9 x 13-tooth combination. These differential gears are stronger, which results in a slightly heavier differential associates. This differential can be plant on the S197 (2005–present) specialty Mustangs only, such as the Shelby GT and KR.

Summary

At this point, you know how to tell the difference between an open up differential and a express skid differential. And you know why you want a express slip differential in your vehicle. You should likewise be aware and confident of how to disassemble and reassemble your limited-sideslip differential and what areas to expect for regarding wear.

Written by Joe Palazzolo and Posted with Permission of CarTechBooks

GET A Bargain ON THIS BOOK!

If you liked this commodity yous will Dear the full book. Click the button below and nosotros will send you an exclusive deal on this volume.

DOWNLOAD HERE