Dumb question I'm sure. I always thought they both were the same thing, i.e power to both wheels.

I found a 3.42 rear end at a salvage yard still tied on to the camaro its from. The cover is gone but all internal components are in view. Drive shaft gone. I know there is an easy way to tell if its posi/ ltd slip, but I can't remember. Could someone please refresh my memory?

 

Just spin one of the tires (or axles) and if the other one spins in the same direction, then its posi. If it spins in the opposite direction, then it is open rear end.

 

thanks...will have to go back and check it out cause I don't remember.

I'm not sure if I want a 3.42 rear anyway. It would be alot of fun, but there does not seem to be much RPM room with the TH700R4. I am worried about highway driving. Presently with my 2.73's, I run @ 2200 RPM at 60 MPH.

Is this something to be concerned about??

 

You should be fine with the 3.42's. I am changing from 2.73's to 3.23's and will be getting less gas milage, but not that bad.

3.42 is a all around good gear for the 700R4. I dont think you could go wrong, as long as the Rear end you get is good.

 

cool....I found one on a salvage car...I'll just pull it and pay $25 for it and keep it around until i decide

 

try looking inside if the cover is off, way easier and 100% fool proof way of knowing

 

Not really sure of what you are asking in the original post. I think you want to know if a posi is the same as a limited slip. The answer No but still Yes. In the 80's the term used was posi but they where truely limited slip. Confused?
A posi is a rearend that turns both wheel the same rate all the time. A limited slip is just that, it will only spin one tire up to a point and then the other will catch (i.e. limiting your slip!!). I don't think GM has used a true posi in a car since the early 70's. . And of course an open rear end just spins one tire all the time.
Hope this answers your question. Later, Garrett

 

No, you're thinking of a locker or a spool. Posi rears are limited slip. "Positraction" was GM's trademark for their limited-slip rear ends. Ford had their own name for it, and so did Mopar, but the GM name is the one that stuck.