Author Topic: clarifacation on Diff Specs  (Read 2090 times)

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Offline bandit nz

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clarifacation on Diff Specs
« on: July 10, 2007, 09:17:46 PM »
I have a question on Diffs, my 81 Y84 TA has a stock diff according to the guy I bought it off.
This subject came up, when discussing the high stall converter and shift kit, he said they wernt of much benifit at present, because the car needed a posi put in the rear.

My question is this, I thought all Y84 TA's came with posi traction rear ends !! is this not the case at all ???
"What we have here, is a complete lack o' respect for the law"
It's only speeding, if you get caught...
Bandit NZ (Stu)
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Offline Joker (§ir£Ğragon)

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Re: clarifacation on Diff Specs
« Reply #1 on: July 10, 2007, 09:26:14 PM »
I'm pretty sure they did. But I've been wrong a lot lately.  :-[
Larry


Offline Rick

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Re: clarifacation on Diff Specs
« Reply #2 on: July 10, 2007, 10:10:12 PM »
Early on (1970-1979), IIRC all TAs had the limited slip differentials.  Towards the end several combinations came with just the open rear gears.  Is yours truly not a posi now? :-\ :-\

Offline bandit nz

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Re: clarifacation on Diff Specs
« Reply #3 on: July 10, 2007, 11:24:32 PM »
Hi Rick
I havent taken delivery of the car as yet, its still on its way down under  :'( waiting  :-[ waiting  :-[ waiting  :-[
The guy I bought it from, who carried out the restoration, is a pontiac fanatic, with ten cars in his collection.
Ive spoken with him by phone a number of times and he leaves me in no doubt that he knows what he's talking about.
Being from a Mechanical background myself, I can normally pick someone blowing hot air and this guy George doesnt strike me as such a bloke.

He said he intended to put a posi in the rear, but never got around to it, so I wouldnt get much benifit from the high stall and shift kit, unless I fitted a posi.
Im a little disapointed it doesnt have one, if this is really the case, but im also supprised that it might not have had one to begin with  :-\
So now im tying to assertain what it should have had, im getting the build sheet etc, but once again this is with the car.
Wishing now I had got him to fax it down to me, so I could work on all of this while waiting  ::)
Cheers
Stu


 
« Last Edit: July 10, 2007, 11:26:36 PM by bandit nz »
"What we have here, is a complete lack o' respect for the law"
It's only speeding, if you get caught...
Bandit NZ (Stu)
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Offline Amtrak

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Re: clarifacation on Diff Specs
« Reply #4 on: July 16, 2007, 10:57:37 PM »
The car came from the factory with a posi if the build sheet has G80 listed in the codes.  But I have never ever seen a second generation trans am that didn't come with a posi rearend.   That is my personal experience though and I have owned over 40 of them.

Offline bandit nz

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Re: clarifacation on Diff Specs
« Reply #5 on: July 17, 2007, 04:59:09 PM »
Thanks Amtrac thats reassuring and id say 40 TA's is a fair indication of the norm.
"What we have here, is a complete lack o' respect for the law"
It's only speeding, if you get caught...
Bandit NZ (Stu)
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Offline kyledyr

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Re: clarifacation on Diff Specs
« Reply #6 on: July 17, 2007, 06:58:39 PM »
As far as I know, 70-80 all Trans Ams came with a Posi standard. 81 did not.

This does not include Firebirds and Espirits and maybe Formulas, though.
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Offline milly

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Re: clarifacation on Diff Specs
« Reply #7 on: July 20, 2007, 11:38:17 PM »
My '81 T/A came with an open rear end. From what I can tell, the Turbo cars got the limited slip (aka posi) rear ends. If your T/A is a turbo car, it may have a limited slip. If it's not a turbo car, there is a good chance that it came with an open rear end.
John
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1996 Firebird

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Offline bandit nz

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Re: clarifacation on Diff Specs
« Reply #8 on: July 21, 2007, 06:07:37 AM »
Ok lets say its not a posi, what can I expect to pay for a good Posi ready to drop in to the diff bell ??
"What we have here, is a complete lack o' respect for the law"
It's only speeding, if you get caught...
Bandit NZ (Stu)
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Offline milly

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Re: clarifacation on Diff Specs
« Reply #9 on: July 21, 2007, 10:23:37 PM »
An Eaton posi from Summit Racing will run about $480.00 U.S. plus shipping. I don't know if any other parts or work would have to be done to install a posi unit in an open diff. You may be better off looking for a whole posi rear axle assembly.
John
1981 Trans Am
1996 Firebird

Central Illinois Firebirds
Ohio Firebirds