Thank you. My email s/b available from my profile too.

 

Everything keeps going back to those RPO codes for that info.

Many years ago I knew a bunch of guys that did builds on street cars for street racing. As I understood it back then, there were 3 types of Diffs: 1. The open rear not good for street because the wheel with the most traction got nothing and the one with the least was the spinning wheel. 2. The Detroit or welded Locker. The Detroit Locker was made as an aftermarket "add-on" & welded was done in a local shop or somebodies garage. A locked rear would only allow both wheels to turn at the same time/rate. Great for the Drag strip. They chirped tires in turns and chattered through U-turns. 3. Positraction a/k/a Limited Slip was a factory option usually reserved for sport models. It was the opposite of "Open" and the wheel with the most traction got it. Later I was told that "Open" was the way to go with loose surface driving like sand or mud. Now the G80 sounds more like the "open diff" for off road than the other. This is very confusing to me.

 

There were basically 3 types prior to the torsen (helical gear type torque biasing) and selectable lockers, but your description of #2 & #3 are off.

The detroit locker is really not analogous to a welded differential as a detroit locker (whether a full detroit locker carrier or a lunch-box locker that fits into a standard open diff carrier) will still allow decoupling of the two axles under certain conditions. A welded differential is similar to that of a solid spool (without the strength even if done correctly) as both fully lock the axles together with no ability for them to move at different speeds.

A posi-trac or LSD is one step down from the detroit locker in that most do not ever fully lock the axles together at any point in their operation. Clutch packs are used to provide torque to the wheel with traction. A few models also have the ability to increase the load on the clutch packs to further promote torque transfer to the wheel with grip.

The G80 has preloaded clutches like a posi/lsd, but also has a mechanism to lock the axles together if it senses too much of a speed difference between the two axles. It also has a governor in it to keep the case unlocked at speeds over something like 25-30mph to limit the possibility of losing control if both rear wheels were to start to spin at higher speeds. In my experience with them, they work good for the vast majority of stock cases and normal situations, but do not like to be abused. Their complexity hinders offroad reliability especially when in the 7.5/7.625 rear axles.

A quick search for "how [insert differential type here] diffs works" in google or youtube will provide even more information on the subject.

 

Thanx again Swartlkk !

I had a feeling you could enlighten me. What I was really after (and maybe DonL too) was a fast way to improve our off road traction without having to dismember Rings & Pinions or rebuild clutch packs. I am willing to take home a whole axle [drums and everything] from a local yard & swap it if we can get the right one with the right gear ratio etc. . If the G80 is the ideal off road diff for our little S10s then I need to get my VIN run and find a list of the meaning of the RPOs in case it's already in there.
If there is another one for example that came with certain Silverado models; I'll go find one of those.
I'm great at list too!
Get this one, but only if it has ___ or the 12th digit of the VIM has to be "G" and so forth

Taking the guesswork and research out of picking one seems like the best way to get the best rear end. The best we can hope for is right wheel drive from the front. 2 more is way better than 1 more in the back.