B-Fake

I had some noise coming from around my front right wheel. It almost sounded like something slapping the wheel well, got faster/slower with my speed. I've been suspecting my cv's are on their way out so I grabbed the cv axle, gave it a tug and sure enough it wiggled around. Took them out while I was waiting for the new ones and the cv's seemed ok. The side gear shaft where the axle bolts to the diff is what was wobbling around, there was also some end play. Time to pull the diff.

I got the diff out (it's a lot heavier than it looks!) and took it apart thinking it must be a bad bearing. The side gear shaft doesn't actually ride on a bearing though.

Here's the shaft


This is the shaft in its place in the carrier

The bearing there is what the carrier turns on in the case.

Here's the where the shaft rides in the carrier.

The bore doesn't appear to be damaged or worn, but it's about .010" oversize. The other side is about .003" oversized which is a nice fit. Both shafts measure the same, wobble in this side of the carrier, and fit good in the other side. The snap ring on the shaft seemed to fit good in the groove so I assume the end play is coming from the fit in the carrier.

So it seems to me that the carrier needs to be replaced. Because of the oil passages in the bore it probably can't be sleeved. I could build up the OD of the shaft with weld and turn it down to fit the O/S bore, but I don't know how long that would last and don't really want to mess with the shaft since it's not the problem.

Has anyone here had this problem and found a solution that doesn't cost $350 for a new carrier? I'm gonna search Craigslist for a used diff to swap parts with, but good used parts are getting hard to come by. Maybe a SAS is coming sooner than I thought lol.

vital22re

iTrader: (2)

I believe that brass bushing/sleeve was replaced with needle bearings in the later yeas as thats whats in my 92's front diff. Thats where your play is gonna be.

B-Fake

I see, sounds like the later years are a much better design. If I find a later model diff are the parts swapable? Anything from '86-'95 should work right?

B-Fake

Looks like I found my answer here. http://home.4x4wire.com/erik/diffs/

vital22re

iTrader: (2)

well you can order the newer style bearing as it superceded the brass from the dealer. That way you won't need to regear and keep your parts or just finda a diff from a newer rig.

MudHippy

I assume what he found answered on the site he provided the link to was this:

The needle bearings mentioned above will not work in a non-ADD diff without also using the ADD side gear shafts(side gear shafts are sometimes refered to as axle stub shafts) that will accept them. However doing so will leave you with the weaker ADD side gear shafts.

So, it's not an issue of bronze/brass bushings vs. needle bearings. It's an issue of needle bearings vs. no needle bearings(and side gear shaft strength).

Also, the end play observed is normal. Adding the needle bearings and ADD side gear shafts won't eliminate that.

B-Fake

Found a guy on CL that has two non ADD diffs left over from SAS projects for $50 each! Hopefully I can pick one up this weekend then swap out my gears (mine are 4:30 his are 4:10) and get my baby back on the road...or off it. Either way it won't just be sitting in my driveway!