Posi-trac was G.M.'s name for their limited slip rear end, equa- lock was Ford's and Sure- grip was Mopars. They all had different names for basically the same thing.

 

Interesting! I've never heard of that with a clutch based limited slip (at least not in the front drive world I'm familiar with..., and all indications I can find are that this is clutch based...

So with 1 tire in the air, 1 tire on the ground, there's -no- slippage (neutral of course), and the in-air tire won't turn at all? How the heck....anyone have details on what they used for an LSD?? Can anyone else confirm that behavior?




Nope...but assuming I don't get chunks of metal out, and this behavior is normal, any suggestions on specs to look for? I haven't even looked to see what the book calls for....


And Miami_Son: Thanks for the link. That one is new to me, but I'd expect that type of locker to at least give me some slippage at low speeds, or at least for a revolution or two.....I was looking for signs of a manual (air, electric, or even linkage) locker in the hope that I'd missed a button somewhere and it was forceably engaged, in which case I could disengage it and not worry. Then I'd scratch my head and try to figure out how I'd missed it.

 

Most of the more expensive oils have a friction modifier included in the oil, but read the label to be sure. If not, it usually comes in a smaller tube you just dump in the fill plug with the oil and drive some figure 8's in the parking lot to get the clutch packs suitably coated. 75w90 is the recommended but I use a heavier oil in the south due to the heat, I believe amsoil makes a 85w140 that I use.

 

With a LSD in the rear you could jack up one wheel and still be able to drive off the jack.

 

Sounds like the clutches are tight, that's a good thing, I think your truck is fine.