Jeep Repair: Grand Cherokee noisy rear end, jeep cherokees, shaft bearing

Question
Doug,

The noise which sounds like a knocking at wheel rotation frequency has been getting worse to the point I have had to look at it.  Particularly as the ABS light comes on now and again indicating, to me, that there is excessive movement or vibration seen by the sensor.

The right rear wheel has about 25 thou axial movement and makes a loud clunk as I pull it in an out.  I cannot detect any radial movement.  I can feel slight axial play in the left rear, but not enough to see or measure.

Looking at my only printed reference, the Haynes manual, it says that if I remove the four nuts holding the back plate to the axle casing, I can pull the axle shaft, bearing and outer seal with a slide hammer.  But reading about Jeep axles in the jeeptech.com site indicates I should have a C-clip axle (Dana 35c with steel diff housing).  As I understand it, I should not be able to pull a c-clipped axle shaft with a slide hammer without first taking off the diff cover and removing the c-clip.

Additionally, if it's a c-clip axle, the outer hub bearing is a roller bearing and if it's a non-c-clip axle, it'll be a ball bearing.  If it has ball bearings, axial play indicates failure.  If it's a roller bearing the axial play comes from a worn c-clip.

Of course, I also found that my rear brake linings need replacing and maybe, with all the accumulated crud that was in there, a rear brake job will cure the problem.

I'd appreciate your guidance, and thanks for volunteering.

Thanks in advance, Peter

Answer
It sounds like you're two sites are confusing differentials.  The C-clip style rear axles are used in corporate rear ends like the 8.25 and 9.25.  These are most common in the trucks and Jeep Cherokees.  The kinds that are held in by the four nuts out closer to the wheels are the Dana's such as the 35 and 44 found in the grand cherokees.

If you've got a grand cherokee then you could have any number of problems such as the axle bearings being worn out (at the ends of the axles closest to the wheels), the carrier bearings worn (carrier to differential case bearings) or even the pinion bearings failing (basically in line with the driveshaft at the differential).

Clunking noises tend to be bearings that have fallen apart or brake hardware that the failed in some manor.  Drums that are out of round (warped or machined wrong) can cause a cluncking noise.  Even drums that have been removed, rotated one lugnut, and reinstalled could cause a knocking/thumping noise.  

Removal of the drum/rotor and measurement of the axle at that point is going to be the only way you'll be able to tell if you've got 1. brake problems and 2. bearing wear.  In addition while you've got it all torn down you'll be able to tell what type of differential you've got.  Also, telling me what the year model and engine of your Grand Cherokee will help too.
Doug