Okay, I understand now. Thanks,
I have no idea how old the bearings are. They either were changed when I put in the posi 4000 miles ago or they are original with about 150,000. It's been over 17 years ago, so I don't remember. Problem is, I can't even torque it enough to get the 20# preload. I've torqued it to 170#, which is as high as my wrench will read and continued on with a breaker bar. The instructions tactransman listed actually say 210# for 1973 and later. Since this is a 73 car, I'm assuming that is the correct min. torque. Unfortunately I can't seem to get it any tighter, since I either lift myself or the rear-end off the ground. There's no longer any play (in and out) but it still spins with little resistance. I gather from what you're saying that not loaded enough is almost as bad as overloading. Guess I'll have to figure out a way to get more torque into it.