4.slow95

Ok so when I bought this 96 cherokee sport 4wd 4.0 auto aw4 trans Jeep I hear a whining coming from the rear end ONLY when there is pressure on the drive shaft. Ie. When I have my foot on the pedal. It goes away once I let off and back again when I accelerate. Carrier bearing? Any help is much appreciated

VTJeep

If there's no vibration I'd say make sure fluids are all full and newish, check the main output bearing on the rear diff and make sure there's no seepage of fluid and lastly, albeit l said "if there are no vibes" but I'd still say make sure the rear drive shaft u joint is good..

Lowrange2

Pinion bearings. I'd put 20 bucks on it. My 8.25 did the same thing so I threw it away.

4.slow95

Yea I had a feeling it was the pinion bearing... that is some serious work and also I don't have the tools. Could it be the u joint?

unit31

It sounds to me like its only making noise on the drive side. So the coast side of the gear is not making noise. This will not be your u joint but movement internally inside the diff. Ive done a lot of work on dana's and ford 8.8's. Im sorry Im not real familiar with the exacts of the 8.25 inners. If its only the pinion bearing its really not that hard. If you can take the cover off and look at the gear teeth on the coast side and drive side, see if the wear appears even and no visible damage. You need to check the backlash and apply some push and pull force against the pininon to see if it changes. If your getting a large variance in backlash then I would assume the bearings are shot.
If the gear teeth look good then I would assume your front pinion bearing is bad. Its not that hard to change. That bearing sits under the yoke and can be removed after the yoke and oil pinion seal are removed. Im sure there is an 8.25 expert on here that can help you with that. Im sorry I haven't messed with that axle yet.

4.slow95

Well that sounds refreshing. I am gonna break it open this weekend and I will let you all know. I'm sure it's a d44 but I will have to see the chart again. Just gonna replace all bearings and seals seeing as they come in a set. With the help of course from dear old pop haha

MarkJRust

Just for my knowledge, how loud is it?

I have a bit of whining and vibes but it's because I need an SYE.

4.slow95

Well at highway speeds it sounds like an air raid siren. So I checked the diff fluid that's good. U joint is practically brand new and I can't move the drive shaft in and out by hand which would indicate a bad bearing right? Also to do the inner and outer pinion bearing would I have to remove the axle shafts?

Jamison

If you have to ask, its over your head...
You will have to remove the axles, carrier and pinion to get the bearings off. you will then need to re-set your pinion depth with shims, and get a new crush sleeve to set the pinion preload. You will need a master install kit if you want to do it right. Some people say you can just take it apart and put it back together the way it was, but there is no way to be certain that you have it correct. You will need a ft/lb torque wrench, and in/lb torque wrench, and a tool to turn the threaded spacers on the sides inside the diff., not to mention a dial indicator and magnetic base to check your backlash once you remove the carrier and put it all back together.
If this is confusing, I would get a professional to do it...

4.slow95

Well my pops knows how to do it and has done it multiple times. I was just curious myself as to how much disassembly was needed

4.slow95

And I just bought the master kit

4.slow95

Update... nothing was wrong. The idiot before me put motor oil in the diff. Explaining the noise. Inspected everything and filled with proper oil. Quiet as a mouse

hardcorecherokee

I am having the same issue on my XJ except opposite its making a whinning noise after and only after i let off the gas i already checked both u joints and theres no play in them at all the only thing i can think of is the pinion bearing. Help please?