Has anyone put a clutch pack in a 8.8? Do you need special tools like they say? Im going to replace all the bearings in my rear end and hope this takes care of a small vibration problem ive had.

 

Wow, nobody has replaced their clutches in their limited slip?

 

I have dug into many 8.8 rears. (On cars that is) You do not need special tools for replacing the clutches but special tools are helpful for reinstalling the pinion gear and crush sleeve. The crush sleeve fits over the end of the pinion gear before inserting the gear through the differential housing. As you tighten the pinion nut the crush sleeve collapses (or crushes). This places the correct amount of preload on the pinion bearing. Too much preload and the bearing wears out too quickly. Not enough preload and you will have excessive play, clunking, or other issues. The special tools greatly assist with this. You can do it without the tools but you just have to know what is too tight and what is too loose. If you have never dug into one of these before that may be difficult. If you do get it too tight and back off to correct then you will need to install a new crush sleeve. Once the sleeve has been crushed it can not be reused.

If you do attempt this yourself then try sqeezing in an extra clutch disc or two. This will help the posi tracttion work better. Also you need to be sure and use friction modifier when you refill the fluid. BTW the new bearings will need to be pressed on the pinion gear and carrier. Not beat on with a hammer.

 

So other than checking the torque of the pinion nut with a dial type torque wrench, what other methods are there? Can I use a dial indicator to check the pre-load / play. Any further info will be useful I plan on doing this project next week. Thanks for your replie robin.

 

The rotational torque can only be checked with the torque wrench or by feel. The torque wrench is your best bet unless you feel comfortable with the process outlined below.

The Ford/Rotunda tool set for rear axle assembly repair contains a flange holder. This flange holder is a piece of steel that is about 20" long, 4" wide, and 3/16" thick. The flange holder bolts to the flange using the drive shaft bolts. This allows you to hold the flange (which is splined to the pinion gear) while you torque down the pinion nut. It is best to use an impact wrench but you need to be careful once it gets the majority of the slack out. Even with the impact, the nut will tighten slowly. After it is tight enough to begin crushing the crush collar be very carful. Use short bursts with the impact and check rotational torque between bursts. How I check the rotational torque is by feel. This is best done with the flange holder attached.

Hold the flange holder at a 90 degree angle to the ground. Release the handle. When the pinion nut is too loose, the handle will swing back and forth. Once the pinion nut is tight enough, the handle will only swing downward once and then back the other direction about 1 to 2 inches. If the pinion nut is tight enough the handle will stop in that position until moved by hand.

This method works best for me and others that I have worked with because checking the rotational torque with the torque wrench is difficult with the rear axle assembly attached to the vehicle. Something is always in the way. If you had your rear axle assembly on a bench then this might work ok. Engineers at the factories probably have everything on a bench when they are dealing with it, but here in the real world we do not. Thats why factory recommended procedures do not always work best for the mechanic in the garage.

If you do not, and you probably do not, have access to a Ford/Rotunda rear axle tool set then you can make your own flange holding tool. Find some scrap steel and make it to the deminsions listed above. Drill the holes to align with the bolt holes in the flange. Two bolt holes should suffice.

Care must also be taken when reinstalling the carrier. Make sure the carrier is seated completely in the housing before reinstalling the caps. Carefully tap the carrier shims in with a rubber mallet. Be patient! The shims can brake easily. The tool set has a "U" shaped tool to tap the shims back in but normally this brakes the shims easier than using the ruber mallet.

Installing new bearings on the carrier could change the back lash. Back lash should be between .012" to .015". Back lash is the amount that the pinion gear will move if rotated back and forth without moving the ring gear. Even with the new bearings you will probably be with in that spec but if you have a dial indicator and magnetic mount then it would not hurt to check it anyway.

Hope this helps.

 

Thanks for all your information. I should be all set for my axle rebuild. Although I do have one more question for you. I run 285/75/R16 BFG ATs, these seem to be to much for the limited slip, I found this website on adding additional clutch discs to the limited slip, what do you think about that. I know you mentioned it earlier but is this going to be over kill and like running with a spool? I think it will give me the added strength I need to keep both of my BFGs turning.

-Thanks for your help, Steve

 

I haven't done a Ford rear end ever, but the technique sounds similar to that used by GM back in the early 70's. What you want to measure is the torque required to turn the pinion gear, by itself. IIRC it was something like 15inlbs of torque. You alternated between using massive amounts of torque to crush the sleeve and then got out your tiny inlb torque wrench to measure the bearing preload. The back to the "big stuff" again. If you knew the inlb reuired, you could fab up your own fixture, like the special Ford part, to give you about the right preload.

 

sounds like you should be able to handle this with no problem.

 

Well before Christmas I rebuilt the 8.8. I must say it went well. I replaced every bearing and replaced every clutch in the limited slip. Actually I added a couple clutch discs to the unit. I am very happy with how everything turned out.

Also I found that my pinion was loose when I went to take it apart. Two things i figured out, that was the vibration i had and never go to the dealer if you want something done right! The replaced my pinion seal for me and did not properly torque my pinion nut. Do not go to the Ford dealer in Big Rapids,MI. I have not had one good experience there.

 

Sounds good! Glad things went well. Now that you know how to do it yourself, you can make sure it is done right.