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Old 11-10-2012, 04:47 AM
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cobalt327 cobalt327 is offline
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Quote:
Originally Posted by PRHeloPilot View Post
So today the guy I've been waiting for to help me change the TransAm rear to my Ford tells me he's not coming this weekend again, 3 weekends in a row. So I went to the swap meet to see what I could find now that I know a little more than last month and I found a '85 Firebird rear with disc brakes and emergency brake and got it for $75!

That just saved me the hassle of removing it from my TransAm so I put my TransAm on Craigslist for sale and already have 2 guys coming tomorrow to buy it.

Now the good stuff. I opened it and every tooth is there and it is very smooth where I can turn it by hand and nothing is binding or catching, very smooth.

As you can see in the pictures it has the GM number in the casting but unless it's still factory inside I understand that number is useless. I also have these numbers I found on the "center thing where the drive shaft connects" that I think is called the pinion. I counted 10 teeth on the pinion but I could be wrong because my neighbor was turning it at 1000 rpm while I tried to count even though I asked him to slow down many times. It was easier to just try again tomorrow if the numbers don't reveal the story. That number is :

22521254 then a small trademark type square with the letters HP inside then 11 41 GM 9 then a very lightly stamped M at the end.

I didn't see anything on the ring but I'll look closer tomorrow because it was already dark outside where the heavy rear is. I did however count the teeth on the ring and came up with 41 teeth.

So how do I figure out what the ratio and if I have a gas guzzler or a cruising differential? Can the numbers tell if it's limited slip too?
The numbers you are concerned with is the *11 41* stamping. That tells you the ratio is 3.73:1. It's an open diff.
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