I had the differential in my 65 coupe set up about a year ago. After that there remained some looseness in the drivetrain that I attributed to the powerglide transmission. My flexplate was on the way out, so I just had the transmission rebuilt this week, so I know the looseness is not in the transmission. How much play should there be in the differential (3.36 positraction)? If I have the car jacked up, how far should I be able to turn one of the wheels before it engages the differential? I don't need to know the degrees of turn, just whether or not it should be approximately 1/8", 1/4", 1/2" etc. Any help would be appreciated.
-
-
Re: C2 Differential slop
With a fresh axle and positraction unit and everthing assembled within OE spec, play should be nearly imperceptible.
Positraction axles get pretty "loose" with age due to normal wear of the clutch pack and abnormal wear of the side yoke ends in many cases. Wear is normally judged by the amount of side yoke end play. A fresh axle should have just a few thousanths. Many probaby have several tenths of an inch end play due to clutch pack and yoke end wear.
You can run a worn axle for quite some time, but they won't take any abuse. One drag racing start or 1-2 powershift may be all that's needed to break a differential gear.
Duke -
Re: C2 Differential slop
Steve:
Although what Duke said is true, I think that you are asking about rotational play. This is a function of the ring and pinion lash. Assuming that all 4 u-joints on the half shafts are tight, then there is always some rotational slop. I think that anything in the range of 4*-6* would be normal. For a tire of 26" diameter, this translates to about 1" angular movement at the circumference.
JoeComment
-
Re: C2 Differential slop
There's no way that ring and pinion backlash will allow one inch of movement at the tire OD if the backlash is anywhere near spec, and if it's not near spec the ring and pinion will not last long. Excess total axle backlash is nearly always attributable to excess differential gear backlash due to worn positraction clutches. The original ring and pinion backlash will not change unless there is significant ring and pinion tooth wear, and if this occurs the axle will howl like a banshee.
The only other problem that could cause excess ring and pinion backlash is loosening of the drive pinion nut.
If a positraction axle exhibits excess lash the first diagnostic would be to run the positraction preload test and check that the drive pinion nut has not backed off. If the positraction preload is not up to minimum spec it is well worn. The next check is side yoke end play. If it's more than about 1/32" it's time to overhaul the axle if you want to restore peak positraction performance and get rid of the excess axle lash.
DukeComment
Comment