That bearing failure is a too-common problem with full size jeeps (wagoneers/cherokees/trucks) that use the D44.
Here's a thread on IFSJA.org (I have an '84 Grand Wagoneer) where they talk about the quality decline of Timken bearings and some other pertinent info:
http://www.ifsja.org/forums/vb/showt...rear+axle+fail
Here's a couple highlights:
"He said a common problem is people will press the bearing and collar together and it deforms the cage. I didn't know if he was right or wrong, but he took a tube, slid it over the shaft, and pressed on the bearing using the inner race of the bearing. Then he pressed on the collar separately."
"This is entirely a derivative of end play. Per the service manual, end play should be .000" to .015". My bearings are 2 years old, 5K miles and measure .310". That is huge! From what I can tell, the thickness of the outer wheel seals have gotten smaller. Most all measure .375" thick. We need to be using the National Oil Seal #9912 that measures .470" thick. It is the only one that is thick any more. A guy has a shim kit and beefy backing plates,
http://www.betterscoutparts.com/Page_1.html This is a good read and why our bearings are dying. A tapered bearing should be fully engaged to last."