I've been through all the searches on how to rebuild a 12 bolt rear. This is my first attempt.

Pinion pre load was set at 22 in/lbs. Backlash is at 9 to 10 all the way around.

Started off with a .035 pinion shim and I've been moving the pinion slowly out of the mesh. I was able to read the pattern up until now. But not sure of what to do now. Did I move the pinion too far out? Or is it all wrong?? Let me know what you think. Thanks.

http://thumb16.webshots.net/t/34/35/3/85/10/2408385100086607076MHbPhZ_th.jpg (http://rides.webshots.com/photo/2408385100086607076MHbPhZ)



http://thumb16.webshots.net/t/14/15/0/21/43/2159021430086607076zSbhSe_th.jpg (http://rides.webshots.com/photo/2159021430086607076zSbhSe)

From what little bit I was able to see it looks like it is close, but maybe a little bit deep. Remove all of that gear marking compound from the gear and just mark 3 teeth in a row. You don't need it all the way around. You need some clean teeth for the pinion to clean it's self on when you turn the gears. This will make the pattern easier to read. Also, if this is a posi rear end use an axle to turn the differential when checking the pattern. You want to turn the ring gear against the pinion. Don't turn the pinion against the ring gear. Try this and post another set of pictures.

Thanks for the tips BGH. I did not know about the axle. It is a posi, the gears are used but all bearings etc.. are new.

I went back and decreased pinion shim, does this look any better? I can't seem to get a good read with the compound. I tried to get a good shot, I know it might be tough to see but any info you could give me would be appreciated. Once again thanks for the help.


http://thumb16.webshots.net/t/57/557/7/23/87/2033723870086607076AmUaIk_th.jpg (http://rides.webshots.com/photo/2033723870086607076AmUaIk)

http://thumb16.webshots.net/t/26/27/5/59/24/2070559240086607076HnRmCn_th.jpg (http://rides.webshots.com/photo/2070559240086607076HnRmCn)

From what I can see it looks pretty good, but the white compound it hard for me to see. I use the yellow compound, but I know that white is probably all that you have. Try running the gears around several more times in both directions to see if it will mark a little more clear.

Finished up with the rear. Went back and forth a few times with the pinion shims and settled in the middle with what I thought looked best. The rest of the rebuild went smooth. I could have sent the rear out to be rebuilt but felt like learning something new, if it doesn't last I will take it to a pro. Thanks once again for the help BGH and Team Camaro for their archives.

Make sure you follow the Mfg's break-in procedures.(NO burnouts yet) :mad: