Hello, my 81 has a knocking noise in the diff. on decell. I had the rear diff. out to service and install a pinion seal. After i had the diff. installed I found the left side yolk had some end play. I compared it to the other side and it was quite a bit more. Is there a spec for this? And how is it adjusted? I did look things over and the pin and side yolk looks ok. I know it is the weaker rear diff. but all I have is the stock engine with no mods. Any info would be appretiated. Thanks.

 

Play in the side yokes is caused by the end of the yoke wearing against the spider gear shaft. The only way to fix it is replace the yoke. Normally this won't cause a noise. I would check all the u-joints in the rear of the car for play, they could cause the noise.

 

I have all new u-joints in it. I have been chasing this noise for a while. I know for sure itis in the back of the car in the driveline. It is starting to drive me crazy. What are the chances the snap ring popping off with the side yolk moving back and forth?

 

If the yoke ends are severely worn the snap tings could fall off because the yoke would have worn past the snap ring groove. To fix it, the diff will need to come out and be rebuilt.

 

if it has that much play the center pin is also most likely worn out, mine looked like an hourglass when I removed it for side yoke play

 

Tom's Differential in Idaho sells a Hardend Pin and he has a real good Price on one of the Yokes but for the other one you will have to go to somebody like Van Steel. If You don't have the Spicer 1350 u-joints You may want to Switch Now. If Your not concerned with bigger u-joints used Yokes are on e-bay all the time. People like Van steel also offer rebuilt Yokes and you could use Yours for Core's

 

Is the noise still there? You may be hearing your clutches clanking. Drive in a tight circle with your door slightly open. I switched to Mobil1 synthetic rear end oil and got rid of that noise.
Bee Jay

 

also worn out clutches cause yoke end play, but not huge amounts

 

Just removed rear end. Side yolk looked to be ok .Guess I better think about rebuilding the clutches. Thanks for the help!!

 

T'm looking for a part number for the Z06 pinion nut. Not that I might need one when I do the diff but I'd like to make the wrench for it ahead of time. Also the tool that fits the pinion gear to hold it while removing-tightening the nut. Or is there a 30 spline shaft that can be used to make one.
Also after reading a lot of the info about replacing the R&P it seems to me that maybe this is a lot simpler than it first appears. There's one big difference with this diff unlike other diffs- 9", 12 bolt, Danas etc. And that is the ring gear has a spec etched on it. This number is plugged into the equation with all those measurements taken with all those special tools. Then this gives the value of the left side shims to place the R&P in it's correct position. Well this was already done when the diff was assembled at the factory. So suppose the R&P you take out and your new one have the same spec? (2.580"). wouldn't this mean you could just install the new R&P with no change in shims? Of course the specs will probably be different but it seems you could just take the difference between the two and adjust shims accordingly. And according to Motiv Gear the pinion is then simply set by backlash using the backlash value etched on the ring gear.

 

Started to reply but it's a 2009 thread

 

548chevelle, I would suggest you create a new post with your question, or contact Gary Ramadi (Forum Member GTR1999) directly via PM or email and ask him the question.

If you start a new thread with your question, Gary will likely respond, but it may take a day or two.

Good luck... GUSTO

 

548chevelle has a C6 Z06, his question in this forum is a mistake..