4th gen posi vs 3rd gen posi ?

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Jan 18, 2011 | 09:23 PM
  #1  
arent they the same? I saw some members here us 4th gen posi are they better than the 3rd gens? I noticed my posi started to act funny sometimes it spins both wheels and sometimes it starts to spin both but then one will hold and the other keep on spinning
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Jan 18, 2011 | 10:30 PM
  #2  
Re: 4th gen posi vs 3rd gen posi ?
Kind of funny I was curious about this today too. I think the 4th gen's use a different style because the 3rd gen's had quite a few problems. Hence why they put the dana 44 in some under factory warranty. Someone will post that knows more though.
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Jan 18, 2011 | 10:35 PM
  #3  
Re: 4th gen posi vs 3rd gen posi ?
but a 4th gen posi will fit directly into 3rd gen rear end without problems right?
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Jan 18, 2011 | 10:40 PM
  #4  
Re: 4th gen posi vs 3rd gen posi ?
Yeah. The axle tubes are wider though so it will affect your current tire position
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Jan 18, 2011 | 10:42 PM
  #5  
Re: 4th gen posi vs 3rd gen posi ?
no I meant the limited slip carrier alone not the whole rear end
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Jan 18, 2011 | 10:50 PM
  #6  
Re: 4th gen posi vs 3rd gen posi ?
oh. Not sure on that. Try doing a search
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Jan 18, 2011 | 11:10 PM
  #7  
Re: 4th gen posi vs 3rd gen posi ?
AFAIK,4th gen through 1997 used the same carrier as
1990 up 28 spline 3rd gen,an "auburn"cone type posi.
In '98 the"torsen"spiral gear type posi was introduced
I bought a torsen carrier that came from a '99 z28
rear and test fit it in a spare '90 housing i had handy
-it all looked good i was going to install this carrier
into the original axle of my'82(to replace a gov-lock
that works great but i do not trust)
Got sidetracked by a tranny drop and repair,so maybe
the carrier swap will happen this year....
Kinda curious how the torsen will behave..
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Jan 19, 2011 | 12:03 AM
  #8  
Re: 4th gen posi vs 3rd gen posi ?
those are good info's so swapping the torsen unit is worth it
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Jan 19, 2011 | 12:23 AM
  #9  
Re: 4th gen posi vs 3rd gen posi ?
I have never see a Dana 44 rearend installed under warranty it the 10 years I was at Chevy
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Jan 19, 2011 | 06:51 AM
  #10  
Re: 4th gen posi vs 3rd gen posi ?
Quote: but a 4th gen posi will fit directly into 3rd gen rear end without problems right?
Info here may assist in your decision-making:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC
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Jan 19, 2011 | 09:21 AM
  #11  
Re: 4th gen posi vs 3rd gen posi ?
Quote: I have never see a Dana 44 rearend installed under warranty it the 10 years I was at Chevy
Yeah that is 2nd hand information someone else on this site told me. So I guess it could be wrong. Sorry.
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Jan 19, 2011 | 09:24 AM
  #12  
Re: 4th gen posi vs 3rd gen posi ?
Quote: Info here may assist in your decision-making:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC
damn good info. everytime i coulnt my teethe on my axles and i always forget I think i ended up with 28 splines
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Jan 19, 2011 | 09:45 AM
  #13  
Re: 4th gen posi vs 3rd gen posi ?
Depending on your axle spline count get one of these and call it a day.

http://www.summitracing.com/parts/DTL-911A415/

http://www.summitracing.com/parts/DTL-912A317/

Forget about getting used carriers.
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Jan 19, 2011 | 02:02 PM
  #14  
Re: 4th gen posi vs 3rd gen posi ?
I have a 4th gen zexel torsen limited slip in my RS. I bought it new from SLP back when they were making them for the 4th gen SS conversions. Its a pretty good unit. It acts like a poor mans traction control. The way it works is if one tire starts spinning the worm gears move in or out and divert some of the torque to the other wheel. When i go to take off and have wheel spin I can feel it as it make the rear of the car shimmy a bit.
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Jan 19, 2011 | 02:38 PM
  #15  
Re: 4th gen posi vs 3rd gen posi ?
I'm certainly no expert here, but I do remember seeing that earlier rears were 7.5in and later rears 7.625. The ZT's from the 4th gens were definitely 7.625 as far as I know. Although I think that the 3rd gen's posi units would swap between 7.5 and 7.625, there might be an issue putting the 7.625 ZT stuff from a 4th gen into a 7.5 early 3rd gen rear.

Like I said, I'm not sure at all - I could be totally wrong - just throwing it out there for consideration.
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Jan 19, 2011 | 02:48 PM
  #16  
Re: 4th gen posi vs 3rd gen posi ?
Thats just the ring gear size. The housing didn't change. so you can swap pretty freely from 1982 to 2002.
Also s series truck used the same rear as well. I have gotten many a 3.73 gear set from s series trucks.
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Jan 19, 2011 | 04:03 PM
  #17  
Re: 4th gen posi vs 3rd gen posi ?
OK - now I know. Told ya I didn't know what I was talking about!
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Jan 19, 2011 | 10:49 PM
  #18  
Re: 4th gen posi vs 3rd gen posi ?
Quote: Depending on your axle spline count get one of these and call it a day.

http://www.summitracing.com/parts/DTL-911A415/

http://www.summitracing.com/parts/DTL-912A317/

Forget about getting used carriers.
i want one!
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Jan 19, 2011 | 11:20 PM
  #19  
Re: 4th gen posi vs 3rd gen posi ?
Quote: I have never see a Dana 44 rearend installed under warranty it the 10 years I was at Chevy
they weren't installed under warranty. from what i heard it was "an upgrade you could buy over the counter"
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Jan 19, 2011 | 11:36 PM
  #20  
Re: 4th gen posi vs 3rd gen posi ?
Dana 44 was avalible from dealer parts at certain times,
but the avalibility seemed to be erratic-seems they were
avalible '82-84,disappeard for a while then came back...
Back in '93 or '94,summit sent me a flyer offering a
limited supply of leftover SLP dana 44s for something
like $600-i tried to get one but they were all gone....
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Jan 20, 2011 | 12:30 AM
  #21  
Re: 4th gen posi vs 3rd gen posi ?
nevertheless i am always keeping my eyes open
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Apr 2, 2012 | 05:15 PM
  #22  
Re: 4th gen posi vs 3rd gen posi ?
http://www.hawksthirdgenparts.com/ca...osiunit-1.aspx does anyone know if this would be a good axle upgrade? and what gears would be best to go along with a T-56 swap? I was thinking 3.73 cuz I still wanna drive it on the street. (infact Im not the best at driving stick yet so I dont plan on racing for awhile lol)
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Apr 2, 2012 | 05:46 PM
  #23  
Re: 4th gen posi vs 3rd gen posi ?
Quote: Dana 44 was avalible from dealer parts at certain times,
but the avalibility seemed to be erratic-seems they were
avalible '82-84,disappeard for a while then came back...
Back in '93 or '94,summit sent me a flyer offering a
limited supply of leftover SLP dana 44s for something
like $600-i tried to get one but they were all gone....
600$ dang. My 93ish catalog shows about 1500$ IIRC
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Apr 2, 2012 | 08:46 PM
  #24  
Re: 4th gen posi vs 3rd gen posi ?
the flyer with the Dana 44s for around $600 was a
closeout special-i still regret missing out on those-
they did not include brakes and IIRC,had 3.54 ratio.
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Apr 3, 2012 | 08:39 AM
  #25  
Re: 4th gen posi vs 3rd gen posi ?
Quote: http://www.hawksthirdgenparts.com/ca...osiunit-1.aspx does anyone know if this would be a good axle upgrade? and what gears would be best to go along with a T-56 swap? I was thinking 3.73 cuz I still wanna drive it on the street. (infact Im not the best at driving stick yet so I dont plan on racing for awhile lol)
Search around on here for several reviews on different types of aftermarket bolt in rearends.

Decide on which one you like, then shop around for the best deal.
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