Grinding and humming...

[charlieboots]

Hi, my 4.0 limited 96 jgc makes a horrible grinding noise from the rear wheels when I turn. The differential has what looks like a leak, or it could just be as its always raining here (uk), are the two related? Someone mentioned the 4 wheel drive selector moght be the problem. Any ideas on how much this sort of fix could run too? As you can tell, I don't know too much about cars!

The humming gets loud till about 40mph then eases off and it is not affected by the brakes.

Your help is greatly appreciated

[JDPascal]

Welcome to AF charlieboots....

If your leak is from the front of the diff housing, and with the grinding and other noises, I would say it likely needs major work.

a complete diff overhaul (if it needs it) would cost about a $1000-$1500 here.

Not good news - sorry!

JD

[dksob81]

JD,

I have some leakage in my rear differential, it seems to ne leaking at the yoke. I don't experience any noises tho. Do you think this is a major repair or just a seal replacement?

[JDPascal]

Originally Posted by dksob81

JD,

I have some leakage in my rear differential, it seems to ne leaking at the yoke. I don't experience any noises tho. Do you think this is a major repair or just a seal replacement?

Likely just a seal.... when you do the seal, check the seal surface on the yoke - wet sand it with 600 wet/dry and varsol. If the groove is really bad, get a "speedie sleeve" to fix it. Cheeper than a new yoke.....

Watch how tight you get the pinion nut when you install the yoke. Check the spec book for the torque. Over tighteneing will take the pinion bearings out!!!

JD

[dksob81]

I was just reading through the FSM on this job, doesn't seem too hard. Setting the PRELOAD shouldn't be too hard sounds just like settings the preload on a wheel bearing on an S-10.

[JDPascal]

Your preload has already been set when the diff was assembled.

All you are doing when you tighten the pinion nut after the seal is installed is make sure that the preload is restored to the same setting by tighteneing the nut to the spec. The torque I use is 175 - 190 ft lb.

I know that the FSM has a serious procedure to check the preload before you take it apart and that is likely good to do but you won't find many techs in the shop taking the time to do that. Just don't use an impact to install the nut - torque it!!!

If you are removing the pinion and replacing the bearings, thats a different story. The crush sleeve is a hard pull to set new preload.

JD

[dksob81]

Tahnks JD,

I was reading the FSM on the and it was talking about resetting the preload and all that.
So I don't have to do all that unnecessary stuff, just retighten it to torq?

[JDPascal]

Originally Posted by dksob81

Tahnks JD,

I was reading the FSM on the and it was talking about resetting the preload and all that.
So I don't have to do all that unnecessary stuff, just retighten it to torq?

you got it!!!

JD

[charlieboots]

Thanks for you help. Just been quoted £1300 ($2300) for the repair! Ouch... might be a while before I drive again...