[69 longhorn]

If you are not changing gears, I would replace the bearings/races on the pinion(yes do keep the original shim that was under the rear pinion bearing). replace the crush collar, & the pinion seal. Pull the nut up on the pinion (use lock-tite), till you crush it enough to get the proper rotating tork, with motor oil on the bearings. Check the book, but in the range of 15-20 Inches rotating(not break away tork) , should be good on NEW bearings. When you plant the ring gear on the new carrier be carefull to seat her flat,(check for burrs , ect) & check the backlash in 4 points to be sure the ring is running straight when you assemble. If you use the same side shims, you should be ok with the new carrier.....unless you notice a change in the backlash. At that point, you need to add/subtract from side to side to compensate. if you notice a spot in the backlash a tad tighter , while checking in the 4 spots(say .0015-.002), you should be able to live with that(assuming .007-.008 backlash). hope that helps, crazyAL