When I went to remove the diff I started to pry it out and it fell loose without any pressure at all. Upon inspecting the side shims one of them looked like it had been turning and had what looks like a shoulder worn in it. Anyone seen this before?

Thanks

 

Does anyone measure the preload on the diff bearings with a torque wrench? If so how much?

 

Yeah, that spacer could've possibly been spinning in there. Whatever the case, it's not good that the carrier basically fell out. It should be in there at least somewhat tight (i.e. needing a prybar to remove it). One thing you can do is buy a set of new, super shims for the carrier. There's a couple of ebay sellers that offer them for only about $20, and they come with more than enough shims to replace the spacers on both sides if you want to. Take a set of digital calipers and measure the thickness of that spacer where it hasn't worn down, then stack up a combination of the new shims to match that thickness. You don't really need to measure the rotating torque of the carrier. What I do is add enough shims to both sides until you have to tap them in place with a hammer and a brass drift. As long as the shims are somewhat hard to get in each side, there's enough preload on the carrier bearings. Of course, you also need to make sure the backlash comes out in spec. (.006"-.010"). If your shims are tight, and the backlash isn't in spec, just remove a couple thousandths worth of shims from one side, and put them on the other side. If the backlash is too loose, remove shims from the right side, and put them on the left side. If it's too tight, remove them from the left side, and put them on the right. I usually do about 3-4 thousandths each time when swapping them, until the lash is in spec.

 

I do have a Ratech install kit that has some shims in it. They do not get smaller than .010 though so I'll have to play around with it some. Does it hurt to reuse the stock shims if they are in good shape?

I mocked it up with the stock RH shim and a few of the Ratech's and got it where if I installed the RH and the diff then the LH shim pack I had to lightly tap it in with the punch as you said. Snug but did not take a sledgehammer to install. That is why the preload question. How can you do anything but guess if you cannot measure it some way?

Anyway that got the backlash to .004 to .006 so I'll try to move it to the left .002. Will it hurt to just add a spacer to the RH that is .002 to .004 larger and that suffice if the lash goes up to within (.006"-.010") since the preload is not exactly as it was from the factory?

 

There's nothing wrong with re-using the factory shim that isn't messed up on the one side. If you can manage to fit another .002" shim in the one side without having to really pound it in there, and it brings the backlash closer to the .006-.008" range, by all means go for it. If it ends up being too hard to drive the shims in, or the backlash is still a bit on the tight side, then naturally you'll have to remove a couple thousandths from the other side. Whatever the case, you definitely don't want the backlash any tighter than .006". I've read in the shop manuals before where they say to actually measure the rotating torque of the carrier to get the preload right, but I don't really know of anyone who bothers. As long as it takes a bit of force to drive the shims in, you'll have adequate preload for the carrier. If the shims are really hard to get in place, another great trick is to put the carrier in your freezer for 30-45 minutes. The cold shrinks the metal down. I've had carriers where I'm just putting the original shims back in, and they absolutely refused to go back in. After the freezer trick, I was pretty much able to push them back in place with my fingers. Also, the correct torque for the bearing cap bolts is 55-60 ft. lbs.

 

Thanks.

It sounds like I'm on the right track with this info and the axle problem hopefully worked out.

 

I played around with the shims and now have .006 to .008. The .006 is hard to read on one spot as it comes up different [.005-.006] depending on how you hold it. But it's mostly 6 to 8.


My factory service manual states: [Backlash at the point of minimum lash should be between .005 and .009 for all new gears]

Preload....I have to pry the unit out with alum. bars and even then it's not easy so I guess it's enough?

Here's a pic of the pattern. What's it look like?

 

Good job man! Looks nice and centered to me. I wouldn't worry too much about the variation in your backlash readings. The last 2 rears I've set up have had a slight variation too when you rotate the carrier to a different position and check it again. Mine ranged from .006-.008" depending on where the carrier was positioned when checking. And yeah, if you have to use some kind of bar to pry the carrier out, it sounds like you're good to go on the carrier preload. In fact, you got your contact pattern centered better than I did on my last one. Mine was a bit closer to the toe of the tooth on the drive side, but it still came out quiet, so no worries I guess. Besides, I've also read that some racers intentionally set it closer to the toe since that's the stronger part of the ring gear supposedly. Judging by your pattern, you should get a nice, long life out of those gears. P.S. Almost forgot to ask. Did you put any kind of load resistance on the carrier when establishing the contact pattern? Just asking because sometimes the pattern comes out a bit different when there's some resistance on the carrier. I usually place a prybar against the flat part of the ring gear and apply some leverage while rotating the pinion yoke with my other hand. This usually makes a deeper and more established pattern in the marking compound. Make sure to do it in both directions so you have a good mark on both the drive and coast sides. Once again, your pattern looks really good, just figured I'd ask if you loaded it up when you did it. This better simulates the conditions when power is applied to the gears when the car is actually on the road.

 

Cool....glad to hear I'm on the right track.

I read a previous post somewhere that said to put a load on the the gear to check the pattern. Matter of fact I could not get a readable pattern until I did.

One question....on the coast side what should the pattern look like?

 

check the backlash on different parts of the ring gear also. every once in a while the unit is warped causing there to be different backlash on different spots of the ring gear, this is rare but you can never be too carefull. painting the teeth and checking contact points should tell you as well but you might have to look very carfully. everything else is exactly how i set mine up. keep goin and good job thus far!!

 

Thanks man.

I was pretty **** about checking the backlash. I checked about 6 points around the gear.

 

Yeah, most carriers end up having a little bit of runout, which can cause different backlash readings at different positions. From what I've read, as long as it only varies by a couple of thousandths, it's fine. Your coast side pattern should be pretty close to what your drive side pattern looks like. If it's off a little bit towards the heel or the toe, it's still ok. The drive side is probably more important to have perfectly centered. Just make sure it's not too close to the top or bottom of the tooth on the coast side, and I would imagine it's about right since it looks good on the drive side. Yeah, I figured you didn't manage to get that good of a mark in the pattern without loading it up, just figured I'd ask and make sure. FWIW, mine was closer to the toe on the drive side, and a bit closer to the heel on the coast side, and it turned out ok. From what I've read, getting it centered from top to bottom of the tooth is the most important part.