I have an 87 Camaro v6 automatic tranny im looking to get rid of my LSD and I found a 10 bolt posi from a firebird I believe its a 2.73 gear. Does anybody know how hard of a swap this would be im not familiar with it and would it still work when I eventually swap it from a 2.8 to a 305 or 350 whichever would be easier?

 

If you have a limited slip differential, you already have "posi". "Positraction", commonly abbreviated "posi", was simpy GM's trademark for the Eaton limited slip back in the 60s, and even after that unit was discontinued, the name stuck.


However, if your car came with a 6-cyl, it probably doesn't have it. More likely, it currently has an "open", or "unlimited slip" if you will, unit.


Swapping a rear is easy.


You will HATE HATE HATE HATE a 2.73 gear. Getting a stock Auburn POS "posi", which is amost certainly wore out and non-functional and non-repairable is not worth putting up with .... that.

 

Posi (Positraction), limited slip, sure grip, twin traction, twin-grip, trak-lok, powr-lok, Safe-T-Track are all the same things. Just diff. words/terms for the same action/part.

A non LSD rear would be an OPEN differential.

Your '87 v6 car should have a 3.42 gear 10 bolt open rear end under it now.

I would take the open rear with better gear over the posi/limited slip with a 2.73 any day of the week.

To answer your question though. A rear end swap is not hard at all. Only 7 bolts to remove, plus 4 bolts on driveshaft, then brake line and E-brake cable, and of course the wheels.

 

Note that if you are just swapping the diff and not the whole rear end then it requires you to properly shim the pinion gear and differential so that they have proper preload and mesh pattern, which is a bit trickier than just wacking on a whole rear end assembly. If not done right you'll end up with gear whine very soon after putting it back together.

 

So what would the difference between an LSD and open would just be that one wheel spins? what does the gear ratio do exactly Sry I'm used to all my front wheel drive cars haha

 

Yes, an open rear end will send power to 1 wheel.. Posi/LSD/limited slip sends power to both wheels.

The higher number (lower gear) gives you better acceleration, and turns more rpm per mph. The best way to put how it feels into simple terms would be to say a 2.73 rear gear vs a 3.42 would kinda feel like driving a manual transmission car and starting off in second gear rather than 1st gear

 

Ok thank you that explains a lot.

 

If you want to learn more in-depth of how LSD's work, youtube is actually a great resource since you can actually see what's happening as they are explaining it. Just search 'Limited Slip Differential' and there will be a bunch of great videos explaining what the difference between the LSD and open diff are.