How Much Play In Rear End?

[87_SR5]

I was curious how much play I should have in the rear end of my pick-up ('87 SR5 4x4). I changed my U-joints today and noticed that there is a little less than a 1/4 turn of freeplay in the rearend (the driveshaft can move that much without the wheels turning). I had my rearend rebuilt not too long ago (less than 5000 miles), so I am not sure what I should expect. It seems this play is noticeable when driving too...like when you let off the gas to let the engine's compressios slow you down, you can feel that shift of the driveshaft.

I think I am going to take the truck back to the shop that worked on the rearend...just to have them check it out. I am having a problem that I can't figure out.

When force is applied one way to the driveshaft (going forward)...and then the opposite force is applied (changing into reverse, or braking with engine compression), there is something shifting which causes a knocking noise (sort of like what it sounds like to knock on your driveshaft...almost like a ping)....I thought it may be bad u-joints, but they seemed tight. I changed them anyways but it didn't fix anything. i don't think it is in the rearend itself...i am leaning towards it being something in the brakes....like something is shifting back and forth. I don't know, I am still investigating it.

Well, thats my problem, but my main question is how much play to expect in the rearend...???

[Full Boogie]

When you had your diff re-built did they use your old gears or did you do a gearswap??

Generally with new gears they should have .008" to .012" for backlash and if used gears are set back up usually .012" to .015" no more. The backlash would be what you feel in your driveshaft, they best way to check it for yourself without pulling the diff out, is to un-bolt your driveshaft again and gently feel the play in the yoke before it turns the tires. If you listen carefully you'll here that play in the pinion/ring gear and obviously those specs are small so if it is a great amount something is wrong. If care was not taken during assembly, it's possible that because Toyota uses a set-up similar to a 9" Ford, that the rings that set in the carrier bearing caps have come loose and the entire carrier/ring gear has moved and naturally it wants to move away from the pinion increasing play in the differential.


Thanks,
Full Boogie