Positraction OEM rear axle? What’s on your differential?

[DeadheadNM]

Can anyone shed light on what tag and fitting were used on the 1/2 ton rear differential for positraction equipped trucks? Innie or outie style fitting?

Thanks.

[Grumpy old man]

Outie on this 67 short bed .

[MJN]

No picture but my old '72 Blazer was posi and had an innie.

[ltdmstr]

My '68 has the tag and outie style plug. Same as Grumpy's photo. I thought it was kinda strange b/c the truck is a bare bones build with 6 cylinder and 3 on the tree. But I did a rear axle swap and confirmed it's definitely a posi.

[60case]

On the 5 camaros I had 69 and 70 had the outie and the 71 and 72 had innie

[DeadheadNM]

Thanks for posting - maybe a switch for 71-72 axles?

If I recall, the fitting threads differ between posi and non-posi rear ends.

[60case]

Threads on both are 1/2 pipe thread

[jeffahart]

I always thought that type of lube tag was dealer installed. Some ratio tags and lube tags were installed by manufactures like Spicer(spicer lube tags are bolted to the cover like a ratio tag) But dealer could still put a ratio or lube tag on an axle. I think if you have a red plug lube tag it's appropriate to put it on "any" car or truck needing posi warning.

2 cents

j

[DeadheadNM]

The parts manual lists a filler part number for 71-72 posi applications. I’m still chasing this down.

[DeadheadNM]

I’ve tracked down what I’m thinking is the correct hole plug and tag for the 1/2t posi rear in 72. The plug is a mushroom shape with an “innie” recess for a socket. Note the tag says limited slip not positraction.

A GM piece (right) next to a reproduction. The GM plug is an earlier year “outie” style.