Pinion Gear marks on Sure Grip.

[Guitar Slinger]

Thirty years ago when I was deep into racing I must have swapped out a dozen 8 3/4 rears. Never once saw one with marks on the Sure Grip unit from the pinion. I recently picked up a 75 Duster with a 8 3/4 rear. It has a 742 unit with 4:10's and a Clutch Style Sure Grip. The pinion nut was backed out and the Sure Grip is marked up from the Pinion. I looked at two other units for sale and both had these marks. What is up with this?

 

[AJ/FormS]

Too much powah,lol.Or too much traction.Or maybe hot-running. Or like you say a pinion nut got loose.
I've seen quite a few.

 

[RustyRatRod]

Pretty common.

 

[Marcohotrod]

the pinion nut loosens, the pinion hits the carrier. torqued to 240 the 742 nut most often does not come loose. less than 240 = problem

 

[Guitar Slinger]

I guess we were stronger back in the 70's.

 

[straightlinespeed]

I had those same marks on a sure grip unit I pulled out of my car when I swapped gears. I agree with RRR, pretty common.

 

[SGBARRACUDA]

Like RRR said. It is more common than you may think. Basically the nut loosens and pinion marks up the SG.

 

[AJ/FormS]

You've probably seen engine-turning, now you have seen pinion-turning,lol

 

[MOPAROFFICIAL]

Too much powah,lol.Or too much traction.Or maybe hot-running. Or like you say a pinion nut got loose.
I've seen quite a few.

I've had two come loose.
The pinion hits the carrier.