Diff Experts: 8.25" Spider Gear Problem

The rear diff in my '01 has been making some noise since I bought it. The dealer where I bought it rebuilt it, but it still makes the same noise. Looking at the invoice it looks like they replaced just about everything. I was in there a couple of days ago, about 6500 miles after the rebuild, to change the fluid, and I noticed that there seems to be quite a bit of play between the spiders and the shaft they ride on.

Is this play normal?

Could this be the source of the noise? It happens from 50-55 MPH.

Can I fix it easily?

I am thinking about putting in some sort of limited slip unit. If this turns out to need fixing I may just do that instead of fixing it.

There are supposed the be thrust washers between the spider gears and the carrier case.
Fairly easy to remove the spider gears.... Jack up the Jeep, put the transmission in neutral, drain the the differential, remove the diff cover, remove the bolt (5/16" wrench I believe) that holds the cross shaft that the spiders ride on, remove the cross shaft rotate one of the tires which should rotate the spider gears out and see what the condition of the thrust washer is..... It adhears itself to the spider gear back due to the surface tension of the gear lube.

Charles

It is a pretty easy disassemble, I had an auburn put in a few months ago and was suprised at how easy it really was. As for adding the auburn the only 'hard' part was grinding the one corner of the inside of the case away to fit it. That took a couple of trial and error fits. As for adjusting it the 8.25 is done with threaded adjusters and a handy item to have is a 4 ft 1" rod, conduit works well, with a bolt or nut welded/attached on the end to slide in thru the axle tubes and do the adjustment with.

CharlesS said:

There are supposed the be thrust washers between the spider gears and the carrier case.
Fairly easy to remove the spider gears.... Jack up the Jeep, put the transmission in neutral, drain the the differential, remove the diff cover, remove the bolt (5/16" wrench I believe) that holds the cross shaft that the spiders ride on, remove the cross shaft rotate one of the tires which should rotate the spider gears out and see what the condition of the thrust washer is..... It adhears itself to the spider gear back due to the surface tension of the gear lube.

Charles

Click to expand...

Thanks for the info on dissasembly. I may take a closer look when I get a chance. Can the thickness and condition of the thrust washer affect the play between the shaft and the spider?

Yup and if it was not adjusted correclty you wll have a sloppy rear too, while it's not rocket science alot of mechanics really have no idea how to do rears, there seems to be a specialized bunch that do that in most shops.