Posi is a chevy term. Fords use "trac lock" (spl?). Limited slip means it uses some form of a clutch device to allow the wheels to move uniquely, for instance around a sharp corner.
so is limited slip better than " trac lock"? and lemme see if i have this down right, both of them get both my back wheels movin at the same time, its just that the limited slip helps them move uniquley from eachother?
basically. They may be a little different internally, but they do the same thing.
The idea is both wheels spin together, with a little give between them for taking tight turns.
The opposite is an open differential. If 1 wheel spins, the rear end will send 100% of it's power to that spinning wheel and the car doesn't move and you get the dreaded 1-wheel peel. WIth a limited slip, both wheels see power, so if 1 wheel starts spinning, the clutches in the differential will grab the other one and send power to the other wheel and puch the car forward (or cause that wheel to spin up).
They are not physically joined. That's a "locker". Both wheels will spin together but it makes taking turns very difficult.
well the reason i was asking is i already have trac lock on my car with 3.08's and im getting 3.73's with limited slip for $50 so should i just pull the ring and pinoin and sell the limited slip?
well im actually getting two sets of 3.37's with trac lock, one set the ring and pinoin is in good shape but the carrier is cut in half, and the other the carrier stuff are in good shape and the ring and pinoin are worn alittle funny. and im not sure about the t lock thats in my car now, it seems like its working fine.
There are different types of meathods used to controll the wheels. My Mustang's Traction-loc uses clutch packs on each side and a S-spring to make the movement of the spider gears stiff promoting equal power to the wheels but really what it is doing is putting power to both wheels but allowing a little slip. Then my truck has the GM limited slip system which I really haven't looked into very much but it will freewheel for a second just like a true open carrier but a second later it will grab both wheels like a locker. It also seems to do this at higher speeds. I belive it uses counterweights that detect one wheel moving much faster than the other and makes it lock.