GM ring & pinion

[69Tom]

Anyone have a good pic of where the marking for the pinion depth setting is on a original set of gears? They're 3.08 gears from 9/70 (if memory serves correct).

I'll take a pic of the stamping on the pinion, but I didn't really see anything that looks like a setting number. There's a 2-21, but don't think that's it. I didn't notice anything on the gear ring.

Thanks.

[60case]

I have only seen pinion depth numbers on Dana gears. The +or- numbers are on the gear end of pinion.

[69Tom]

So in this case, am I just doing a lot of trial and error with marking compound, or is there a set standard depending on the ring and pinion number? I assumed each would be different, but maybe not.

If need be, I'll purchase this book if it has measurements:

https://www.themotorbookstore.com/di...ir-manual.html

[3767]

For me it was trial and error. Used the original set of shine to start with. Used marking compound to see where the two meshed together and went from there.

[Bigdav160]

GM dealers used a pinion gauge block to get the required shim thickness. No measurement on the gear

[A1971Blazer]

.035 is where I start if there is no dimension on the pinion gear....if it has the original pinion...start with the same shims that were in it...

[69Tom]

I purchased the ring and pinion from a member here on the board. Sadly, it did not come with its original shims.

[Bigdav160]

Originally Posted by 69Tom

I purchased the ring and pinion from a member here on the board. Sadly, it did not come with its original shims.

The shim stays with the housing, not the gear

[69Tom]

Originally Posted by Bigdav160

The shim stays with the housing, not the gear

There's usually a shim under the bearing on the pinion. With that said, I bought the posi unit from a member on the board here and that too did not come with any shims.

[randy500]

Even if you knew the + or - for the gear set, its just a starting point, you probably dont even know your housing + or -
Those numbers just help get it done quicker.

[3767]

Use the shims from the current rear end. It's just a starting point. U can buy a shim kit if needed to complete. This will only b needed to bring backlash n spec and help get enough shim to set pinion. Use your originals first before u order something you may not even need. Keep right and left ring gear shims separate. I put each n a marked zip lock bag. The tool that a previous poster mentioned is a good tool but u can get it done without it.

[71meangreenc10]

I have a 3.07 laying around and I can pull the bearing to see the shim and mike it if you like.

Smitty