What am I looking at here? '71 SS 10 bolt rear end

[Spanky McWeasel]

Hey there, font of all knowledge, and a happy 4th to those who celebrate

Finally got to popping the cover off the rear and this is what I found inside: yes, it's the 3.42 gear that the external stamping and number cross-reference suggested it would be, but when I spin the driver's side wheel, the passenger side rotates with it. This isn't an LSD, right?

 

[Spanky McWeasel]

Had to reply to my own post because my attachment didn't want to show up :/

 

[Fbird]

YES that is a LSD
Both wheels spin in SAME direction

 

[Spanky McWeasel]

YES that is a LSD
Both wheels spin in SAME direction

Welp, Christmas came early, I guess

Is that a genuine GM Posi-traction or some aftermarket conversion?

All the pics I've seen/found seem to have four, very obvious coil springs, whereas this has that kooky "S" spring affair between the spider gears.

Cheers,
Rik

 

[Twisted_Metal]

The “S” spring was what they had in a factory unit.

 

[70lt1z28]

12 bolts had the 4 springs.

 

[junkyarddawg]

That rear end is what they call a 8.5 "corporate" 10 bolt rear end and positraction unit, not to be confused with the older 8.2 (10 bolt) and 8.875 (12 bolt) "Eaton" units which had the 4 springs and pressure plates which pre-load the clutches. The 8.5 rear end you have there will take a lot of abuse as long as it is setup correctly and maintained with the correct fluids.

 

[1997]

I'm not trying to steel this thread. but in my search for answers I came across it . So I have what I believe to be the same unit in my 74 Z the spider gears are toast ..I've yet to pull the axles but will be in the next few day . I'm assuming I've got 28 spline axles ? were do I find the correct parts and the knowledge for the replacement of the spider gears ?

 

[OFLHLG]

On the same subject….. what does this look like to those who know?

 

[hd_cat]

Had to reply to my own post because my attachment didn't want to show up :/

GM Factory clutch type differential