I'm in the midst of rebuilding my front and rear diffs with the 5.38 R&P sets. Here's what I've learned in the process of preparing...

If your R&P are getting sloppy, you might have a problem with wear in one or both of the pinion bearings. There is a shim between the base of the pinion gear and the inner bearing that adjusts the front/back relation of pinion to the ring gear. That shouldn't need adjusting, ever, unless you are installing a new R&P set. If your gears are worn from normal usage, you can try adjusting the backlash by moving the carrier/ring gear towards the pinion gear using the carrier's side bearing adjustments. Any wear in the gears related to slop in the pinion can only be caused by the pinion bearings wearing and/or the crush sleeve between the pinion bearings getting compressed from a high load of some sort that caused the pinion to deflect a small amount. The crush sleeve is a cheap alternative to the solid pinion spacer. It's a one-size-fits-all $$$ saver for auto builders. But it's also a one-time use part. Both are used to set the physical distance between the pinion bearings so that the bearings have the proper preload on them at installation. The solid spacer, which can be adjusted with shims, can't be compressed. If it does happen, the force would destroy your diff anyway. The crush sleeve, on the other hand, is compressed by torque on the pinion nut until the proper preload is achieved. If the sleeve is over-compressed, it's toast. What I'm getting at is that if the pinion bearings are worn and/or the crush sleeve gets compressed, the pinion will slide forward and back in the housing. And even microns of movement, over time, will accelerate wear of the gear teeth. That said, if you have an issue with the pinion, you'll have to replace the bearings. And if you going to do that, you might as well rebuild the whole 3rd member... to possibly include a new R&P set too.

Hope that helps... <img src="/forums/images/graemlins/kewl.gif" alt="" />