My cars rear end was ruuning fine post a gear swap unitll the nut on the rear end yoke came loose because they didnt use any loctite on it which is another story for another day .

It also leaked oil up thru the splines on the pinion shaft out from under the pinion nut too becasue they use any sealer like they should have.

So after that deal i would not let them touch my car again and i removed the rear yoke,cleaned the oil out,installed some slicone sealer,reassembled the yoke to pinion, and retrq'd pinion nut to approx 125 lbs with loctite and all was ok, leak stopped too.

Now since the pinion nut came loose the car/drivetrain picked up some very slight vibes when off throttle at times that goes away when i reapply some power which is still the same after i retrq'd pinion nut to only 125lbs because i was tryting to not over trq the pinion nut whch could change gear setup/clearance .

BTW,the vibes were not present before pinion nut came loose.

Also,If i get under the car and grab the d-shaft and pull it from side to side letft to right i can now get a little play/clunk clunk if i pull hard enough which has been that way now for i hate to admit 2 seasons /approx 1k-1,500 miles and has not gotton any worse vibes wise or when pulling side to side on the d-shaft too but it's always in the back of my mind being a little loose hoping that not going to damage the rear end/gearset /etc.

Since it has not seem'd to get any worse vibration wise so far or pinion slop when i grab it hasent increased any either that i can tell showing there's maybe no damage being done yet or its minimal damage at this time esp since i dont abuse the car .

My question after all that (LOL!!!) is could that little play in the pinion bearing be taken up by simply loosening up the pinion nut again (becasue i used locktite on it when i 1st trq'd to 125lbs), then reapply some loctite ,re-trq pinipon nut to 150lbs or even a little more then 150lbs trq untill the side to side play goes away ?

Again,the Car isnt abused at all,has an m20/331 gear with mild 396 with maybe 375hp/440lbs trq ,i only go thru the gears once in a while with no burnouts and no starts from a dead stop,am always moving before going to WOT rowing thru the gears once in a while.

Should i leave well enough alone and not address it unless the vibes get worse since it hasent changed in 2 seasons thus far or what?

Or am i just barking up the wrong tree here because rear ends are not my strong point when it comes to wrenching these old cars which i know your a expert/pro at?

BTW, where can i get a new replacment pinion nut for the original stock 12 that came in my 69 including pt# if possible?

Thanks...Scott





Scott

You should replace it with a 10 bolt with some 2:73's, and use a high zinc gear oil in it.;)





:D

Ignoring the side to side movement (enough to get a clunk noise) is just asking for trouble. I'd be inclined to pull it apart and install a new bearing and crush sleeve.

Scott, being a victim of two pinion nuts coming loose (loctited too!), I now double nut them.

are you sure it is really side to side your feeling, not just some back lash on the pinion/ring gear-sometimes b4 the crush sleeve gets really crushed, the yoke/washer can get a bugger on it, give a false "feel" like it crushed, when it didnt (i bevel the inside of the washer so the nut cant squeeze the washer into the threads) so it may have never got tight-just a thought, noise might be pinion depth-you really need to pull the guts, ck pinion preload

If it was my car I would remove the axles and differential and install a new set of pinion bearings, crush spacer and reset the bearig preload. Torquing the nut to 125 foot pounds should have taken care of the problem, but in this case it didn't. The only way to be sure that the bearing preload is right is to do it over again.

The pinion nut is still available from GM. I don't have the part number with me right now. I also have a few on the shelf.

Scott,
HOLD ON A MINUTE!
I have gone back and re-read your comments.
You said you grasped the DRIVESHAFT and were able to move it left and right.
IS IT THE DRIVESHAFT ONLY THAT IS MOVING L&R, OR IS THE PINION YOKE MOVING L&R????????
If the driveshaft is moving and the pinion is not moving----------------then it may be the U-joint that needs to be replaced! Much better replacing the U-joint than tearing into the rear!
Check it again and make sure just what it is that is moving!!!

Its happened to me, but when i had my driveshaft out, I put it back in and I had vibration. So I took it out and turned it 180' on the yoke and put it back in and the vibration went away.

Dave

I agree with Dave427 as far as turning the driveshaft 180 and then check for vibration with a short run somewhere. Before you rip into her. Not to say that the other comments didn't deserve some merit. But always check the easy stuff first, its way easier on the pocketbook.

Thanks BGH/Tom,Guys.

Unfortunately its not bad universals,i had the driveshaft rebuilt with new ujoints,new trans and rear yokes,and had it ballanced when i had the 331s installed .

The side to side movement when i grab the d-shaft back at the rear is definately movement in the pinion & bearing when i push/pull side to side.

There is also a new tail shaft bushing in the m20 too.

There were no vibes at all untill pinion the dang pinion nut came loose and again yes there is definately side to side movement/slop in the pinion.

It's not worse 2 seasons/1500 miles later , the vibes are not worse and the side to side slop in pinion isnt worse either.

Now I only feel the vibes once in a while when i let off the gas just enough to release some of the power load off the drivetrain other then tha i would not even know there were any vibes or that there waqs some side to side slop in the poinon beraing.

The right way to do this would be to have the ring & pinion re-setup properly ,i was just hoping maybe there was something i was not aware of that could be done to possibly get arround having to redo the rear end setup.

But unfortunately it looks like a full rear setup will have to be done in the near future as time & $ allows unless someone chimes in with a silver bullet fix,yeh right/LOL!!!!.

Thanks...Scott

Scott. Easiest and cheapest fix ( at this point ) is to pull the cover, axles and carrier. Then pull the pinnion and see what's going on. If all's well, pinnion bearings and a crsh sleeve are relatively inexpensive - compared to losing a pinnion gear and having metal trash the carrier.

I don't think a full rebuild would be needed, just the pinion bearings. I think I can get a pinion kit that has the pinion bearings, crush spacer, pinion nut and seal. That is all that I would replace at this time. Get the preload set right on the bearings and it should be good. Then just put the differential back in and check the backlash, put in the axles and finsih the job.