Guys,

I think I finally tracked down the source of a vibration that seems to occur under load like when I am going up an incline in overdrive at about 70 MPH. When I touch the brake to disengage overdrive, the vibration goes away.

I have found several issues and replaced shift solenoids, u-joints, motor mounts etc. I now discovered that the rear differential pinion has some play in it. I would like to replace the bearings, seal and crush sleeve. I rebuilt this rear myself a while back but I paid a mechanic to set up the preload, shims, etc.

I would like to try it myself this time. If I am just replacing the pinion bearings, do I need to change any of the shims to adjust preload or can I put everything back together just the way it is? How would I set the preload on the pinion bearings?

Thanks for any advice.
Jeff

 

Bearings should be fairly consistent. You should be able to use the same shim stack thickness if using the same pinion gear.

 

I used Timken bearings when I rebuilt it and plan to use the same again. Everything I read about replacing the bearings talk about measuring the preload with a torque wrench and counting the threads on the pinion shaft before removing the nut. If the pinion is already a little loose (because the bearings are worn) I would think measuring the preload would be useless. Should I just forget about measuring it before removal and set the preload between 2.7 - 3.6 Nm (20 - 32 inch lbs.) on the new bearings?

 

Yes, set the preload as required for new bearings.

 

Thanks. I'll give it a try and let you know how it goes. I need to find the part number for the Timken pinion install kit. I checked out part number DRK-321 but is appears to come with carrier bearings that I don't need. Might just buy the bearings and crush sleeve and seal separately.

 

Just wanted to bring closure to this post. I rebuilt the diff using a Motive Gear Master install kit that inclluded all new Timken bearings. I found the pinion had a little play in it and I found signs of movement in the bearing races of the pinion. I set the preload to about 25 in-lbs and the backlash to 0.007 in and I am happy to say the vibration is gone. I did not find any wear in the bearings so I think either the guy I paid to set up the rear last time did not set the preload tight enough or the pinion lock nut loosened up a bit.

All is good now. Thanks for the help!