I just bought a 92 , 1/2 ton 4x4 mainly for parts for a CTD project. the tag is gone from the underside of the hood so how can i tell what ratio diffs are in it. it's not a posi so i can't count therevs of the driveshaft. the GM trucks all have a code stamped into the right axle tube. thanx, crossy

 

You can still count the revs. of the driveshaft to tire rotations.
If the axle has no limited slip, the one tire will spin twice as "fast".
So the rear driveshaft should spin about 7 times to one tire rotation for 3.55s, 8 plus for 4.10s.
I think I am getting that right....

 

Yep.

How clean is it under the hood? Can you read the options sticker?

 

Pull the diff cover, as it's stamped on the gear.

 

It's probably a 9.25/3.55

 

it's a 9.25, but the last 92 I had with 318 magnum and a 3.91 well . That thing was a screamer . lol