Transmissions and Drivetrain Need help with your trans? Problems with your axle?

just picked up a posi rear have some questions

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Old Aug 6, 2007 | 08:00 PM
  #1  
xgtharo86x's Avatar
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From: Oviedo,Florida
Car: 86' Trans am
Engine: 85 LG4-non cc carb(building a 350)
Transmission: Rebuilt 700R4,vette servo,2200stall
Axle/Gears: 2.73 Posi
just picked up a posi rear have some questions

i just bought a posi rear and he says it ether haas 2.73 gears or 3.73....did they even make a 2.73 posi...well im puting it in thiss weekend and seeing if it changes my speed to tell...if it is a 2.73 wut is the best gear set i can get for it i heard the carrier is bigger then other ones...its a new rear bought about 6 months ago from a speed shop....thanks
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Old Aug 6, 2007 | 08:12 PM
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DJP87Z28's Avatar
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Car: 1987 Black IROC-Z (SOLD)
Re: just picked up a posi rear have some questions

Check the ratio before you install it. 99 44/100% sure it is a 2:73 and yes they came with a limited slip (RPO G80). Very few 3rd gen cars had a 3:73 ratio (83-85). Hell of a speed shop if they could not tell you the correct ratio.
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Old Aug 6, 2007 | 09:15 PM
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From: Gladstone, Missouri
Car: 91 Camaro RS
Engine: 5.0L TBI (ebl inside)
Transmission: T-5
Axle/Gears: 3.42 lsd 10 bolt
Re: just picked up a posi rear have some questions

Originally Posted by xgtharo86x
i just bought a posi rear and he says it ether haas 2.73 gears or 3.73....did they even make a 2.73 posi...well im puting it in thiss weekend and seeing if it changes my speed to tell...if it is a 2.73 wut is the best gear set i can get for it i heard the carrier is bigger then other ones...its a new rear bought about 6 months ago from a speed shop....thanks
What are the numbers on the ring gear, (xx:xx)? This will tell you the ratio. The 2.73 lsd would be much more common, as a 3.73 lsd was only offered for a limited number of years. If it is a 2.73 carrier, the highest numerical gear you could get would be 3.08, although you could run a spacer and higher gears.
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Old Aug 7, 2007 | 05:29 AM
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From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: just picked up a posi rear have some questions

Originally Posted by DJP87Z28
Hell of a speed shop if they could not tell you the correct ratio.
Here's how to determinne what ratio the rear is (jerk the diff cover and look): numbers are stamped on the ring and pinion:

41 : 15 = 2.73
41 : 14 = 2.93
40 : 13 = 3.08
42 : 13 = 3.23
41 : 12 = 3.42
41 : 11 = 3.73

JamesC
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