10 Bolt C Clip Information

I have 2 rear axles: a spare 2.73 non-posi and a 3:08 posi unit installed on the car. I felt that the posi unit had excessive end play on the axles while the non-posi unit had little or no end play. The end play is the play felt when you pull and push on the axle shaft.

The 10 bolt rear end uses C clips to stop the axles from falling out and the pinion shaft stops the axles from moving in. Since I had to take the axles out to install rear disk brakes on the posi unit, I decided to take the spare non-posi unit apart, make some measurements and use the best (least worn) parts on the posi unit to reduce/eliminate the end play.

C clip and stuff

Pinion shaft on right, C clip in center and axle showing spline and C clip groove

I measured the play between the pinion shaft and the axles on both diffs. Then I measured the wear on the C clips (thickness), the width of the C clip grooves on the axles, the pinion shaft diameter wear (shiny spots on the photo) and distance on the axle shafts between the end and the C clip groove. Here's the results:

	Pinion to shaft	 C clip groove	C Clip 	Axle end  Pinion shaft

Non-posi	0.010"		0.179"	0.150"	0.250"
		0.015"		0.178"	0.150"	0.249"

Posi unit	0.045"		0.178"	0.147"	0.245"
		0.060"		0.178"	0.148"	0.225"

The pinion to shaft measurements are what I was feeling as end play. The non-posi's 0.010" and 0.015" play feels quite acceptable and what I would call tight. The posi unit's 0.045" and 0.060" play feels loose and as if something is wrong.

The play is the result of wear from the end of the axles against the pinion shaft. On the posi unit there is 0.015" of wear on the end of the axle and 0.025" on the other side. Add up the minor wear on the pinion shaft, C clip and groove and you get the "excessive" end play feel. I swapped the posi and non-posi parts and ended up with a much tighter feeling rear end ;-)

By the way, I couldn't find any specifications on axle movement end play any where. It's like a topic that no one wants to discuss. Anyways, hope this info clears up some things.

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Copyright April, 2011 Eugene Blanchard