1968 8 3/4" "741" Sure Grip End Play

[JimKueneman]

I replaced the axle seals the other day. I read about the spacers that can fall out of the differential in various places so I was looking for them. I also removed the differential to replace the gasket and clean the housing out. I flushed the differential out and did not notice anything loose or falling out. I have it back together and I can't adjust the nut to the point where there is no play. There is excessive play in both axles. That said I stupidly did not check the old endplay before I took it apart so I don't know if it was like this before or not. Also I don't see any "spacers" in the service manual for this axle. Any thoughts.

Jim

 

[Darthomas]

Is the "Thrust Block" there?
If your differential came out of a car where someone had put in "green bearings" the Thrust block was removed, and you'll never take up the axle end play.

 

[JimKueneman]

Sorry I meant to say "buttons" are mentioned in various places and I don't see them in the diagram. I guess I have to pull the damn thing apart again…

I have to say I can't seem to make the opposite axle move by sliding the other in and out.

 

[Oldtimer]

I'm not sure where you are at with this repair. Assuming you have everything buttoned up and simply wanting to adjust rear axle end play, here is how I did mine. Obviously, have both axle housings clear of the ground. The adjuster ring should only be on the passenger side. If not, someone may have installed a replacement axle, using a driver's side axle which has not been modified to include the adjuster ring. Conversely, someone may have replaced the driver's side axle with a passenger side axle, leaving the PS adjustable retainer affixed, rather than removing it and replacing it with the correct non-adjustable DS retainer. Should this have happened, you will have no idea where the correct starting point is going to be, compared to a factory setup. I am hoping everything is correct. If so, torque down axle retaining bolts short of final specs. If not already done, release PS lock tab. Use hammer and drift punch adjuster plate to rotate inward until no end play. Back off to approx. 0.004" end play. Go to driver side and kick the **** out of wheel to help align differential mechanisms. If passenger side end play has increased, rotate adjuster 'til tight, back off to 0.004". Rinse and repeat kicking-adjusting process until 0.004" end play is stable. Torque axle bolts to final spec. Finally, turn adjuster to remove end play and back it off 4 notches to create approx. 13-23 thousandths " end play. Replace lock tab. Add shims to inside differential if end-play adjuster runs out. It's always wise to refer to the manual, or by all means, use your own preferred technique. FYI, I was also told, that around the time of this model year, axles out of a Coronet and perhaps others, measured 29" from the inner flange edge to the end of the axle. If used, as a replacement axle by mistake, this would also create the problem of not being able to eliminate end play, as the correct axle length for the 68 GTX should measure 29-5/16". No doubt others here will have even better advice. Good Luck

 

[JimKueneman]

Figured it out. The adjuster gets REAL tight when the axle bolts are tight. I ended up loosing the bolts then slowly screwing the adjust in then snugging up 2 bolts to check the endplay. I finally got zero endplay and was able to back it off a few ticks with the bolts tight. It is good now.