Drivetrain Any Advice Or Tips For Replacing Trac-loc Clutch Packs?

MFE92 said:

That's...odd. *I* wrote that, word for word, years before I was a member here. I've since updated it quite a bit:

It helps if you have a good manual but the instructions that come with
the kit are pretty good. The part number is F5AZ-4947-BA and it’s generally around $70 or so at Ford dealers. You may be able to find it cheaper on the net. Get about 3 quarts of 80w-90 gear oil. If you use synthetic you probably shouldn't use much friction modifier. If you want absolute max trak-lok action and are willing to put up
with some unsettling noises from the rear end, don't use any modifier at all. It just makes the clutches more slippery so they don't chatter. I chose to use half a bottle the last couple times and I'm glad I did since this is my daily driver, autocrossed and dragraced for fun. Anyway, here goes.

1) Jack up the rear end and support with stands.
2) Loosen the diff cover bolts, removing all but the top two so you don't take a gear-oil bath
3) Pry the cover loose and drain the rear into a pan.
4) When threat of bathing is gone remove the top bolts and pull the cover off
5) Scrape/wipe out the bottom of the diff.
6) Now is a good time to soak the new clutch discs in friction modifier, the need to soak for 20 minutes at least. If not friction
modifier, at least gear oil -- you don't want to put them in dry
7) The shaft going through the center of the diff is called the pinion shaft. It's got a lockbolt on one end. Undo the lockbolt and push the shaft out. You’ll only want to push it in a little bit so you can still rotate the assembly and pull it out toward you. There isn’t enough clearance to push it all the way through or to turn the assembly if you’ve tried.
8) Remove the wheels and brake drums, leave the other brake hardware alone. Push the axles inward, and you'll see the c-clips that hold them in place. Remove the clips and pull the axles out gently -- don't torque the bearings on the way out and don't let the axles hang, just remove them.
9) Get a grip on the s-spring and pull it out. You may need to punch it with a hammer to get it started, and keep a damn good grip on it when you remove it you don't want it zinging around.
10) The gears you see are the pinion gears and the side gears, called spider gears. Rotate things until the spider gears pop out, then pull the pinion gears out too. Inspect for damage.
11) Now you can simply slide the clutch packs out, use the tabs on the plates if necessary. Make sure you get them all out including the shims. NOTE: Inspect the clutches carefully. You will likely find there’s a lot of material left on them. Hard-core corner-carvers have found that the best, longest-lasting performance upgrade for the traction-lok is to re-shim the existing clutches so the diff is as tight as possible rather than replacing the clutches with new ones. The reason is the new clutches will have miniscule high spots that wear down rather early, quickly diminishing the locking effect you are trying to achieve. The older clutches, if they have plenty of material left, are already worn-in and re-shimming them keeps things tighter longer than using new clutches.
12) Reinstall whichever clutches you choose to use with the steels in the proper order, using a shim at least as thick as the ones you removed. You want to use the thickest shim you can while still being able to get the spider gears back in. Forget about using the set-up tool and all the special measurements, if you can get the spider gears back in you're all set. Note: Each clutch pack is made up of a series of Frictions and Steels and in the factory order they go F-S-S-F-S-S-F. However, if you re-use the best two of your old Frictions in place of one of the new Steels you can re-stack them in an order that makes the diff lock better, which is F-S-F-S-F-S-F, which is the same number of total elements. You may have to trial assemble it a couple times to get the right shim so it's just loose enough to get back together, barely.
13) To get the gears in, it helps to have a helper turn the now-temporarily-installed driver's side axle while you lock the ring gear in place. The spider gears will squeze into place. They are perfectly aligned when you can get the pinion shaft back in.
14) Re-install the s-spring. Or don’t. It’s only there to help in really really low-traction situations. Leaving it out will not hurt the locking power of the unit under normal conditions. Getting it in, if you choose, can be a ****. Try holding it against its slot with a pair of channel-locks to get it squeezed down a bit while prying it in with a piece of 2X4 using the swaybar as a fulcrum. Alternately, do the same but whack it with a mallet. It should pop in. If it doesn't, try using a 1-1/2 inch hose clamp to squeeze the spring so you can insert it. Then cut the clamp and slide it out.
15) Re-install the axles by pushing them all the way in, installing the c-clips, and pulling the axles back out against the clips which are now recessed in the housing and locked in place.
16) Reinstall the pinion shaft and make damn sure you put it in the right way so the new lockbolt can be installed. And do not use the old lockbolt.
17) Use gasket maker on the diff housing and reinstall the cover.
18) efi85gt posted a terrific tip for filling the diff. Forget the fill plug. Let the rear end drop as low as you can and remove the little vent cap on the top of the right side axle tube. Clean the area around it carefully and you’ll be able to fill it through this hole with a fraction of the stinky mess you get when you use the “fill hole”. Looks like this: http://www.corral.net/photopost/data...um/baer024.jpg

But you should still remove the fill hole bolt so you know when to stop filling, which is as soon as it starts to come out that hole. Wipe the tip of the bolt off, it's magnetic and the silvery paste is metal shavings.
19) Fill the housing until it comes out the fill hole and replace the plug.

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FoMoCo17 said:

the carbon fiber clutch pack is the way to go ... and I tried the S-pring supplied but it didn't look right so I took it out and got a new regular s-spring from Ford. Do not forget the limited slip additive as you will need it more than before to quiet the rear down on turns. The shim packs go on each side and need to be tight! You use and measure the shim packs that you pull out as the gauge for the new ones. These shim packs are then added or subtracted so that your backlash is set properly w measuring it with a dial indicator. The overall shim pack remains the same once it is established but backlash is adjusted by pulling from one side and adding to the other. If you see that the big ears that ride against the hub have marks in them you then have to increase the overall shim pack a few thousanths because the rear was moving around a bit from being built by the factory. Ideally the rear side gear assembly should have to be lightly hammered in with a deadblow rubber hammer to prevent any shifting or looseness. If your not changing more than one point in gear ration the pinion shim used at the factory should be good and can be ckecked with the white runout paint. Leave collapsible pinion spacer out and set pinion bearings to zero lash in all checks. You will have to assemble and disaaemble a few times to get all measurements spec'ed out accordingly. Once the rear is correct then you can install the collapsible space and crush it and still have the same pinion depth as measured with zero pinion bearing clearance. Always double check everything especially measurements! Hope these pointers help you! Also get the FMS gears they come highly recommeneded and I have not had a problem out of my rear whatsoever ... probably better than when Ford put it together!

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