# refresh my memory on rear ends



## 68gtohawk8369 (Oct 26, 2009)

limited slip is when the car is jacked up both rear wheels off the ground and when one wheel is turned the other turns in the opposite direction and posi same situation both wheels will turn in the same direction when turned?I have read Rukee's response on many of the rear end questions I have a 10 bolt open and was interested in possibly have an auburn posi put in what should I expect to pay to have this done with all new bearings etc.. etc . From what I have read a 12 bolt chevy is the way to go but I think for the same cost or possibly even cheaper I could get the 10 bolt rebuilt with the gear I would like instead of a used 12 bolt what do you guys think.


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## freethinker (Nov 14, 2009)

68gtohawk8369 said:


> limited slip is when the car is jacked up both rear wheels off the ground and when one wheel is turned the other turns in the opposite direction and posi same situation both wheels will turn in the same direction when turned?I have read Rukee's response on many of the rear end questions I have a 10 bolt open and was interested in possibly have an auburn posi put in what should I expect to pay to have this done with all new bearings etc.. etc . From what I have read a 12 bolt chevy is the way to go but I think for the same cost or possibly even cheaper I could get the 10 bolt rebuilt with the gear I would like instead of a used 12 bolt what do you guys think.


what do you plan to do with the car? 12 bolts are getting hard to find and are expensive.


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## Rukee (Feb 8, 2007)

68gtohawk8369 said:


> limited slip is when the car is jacked up both rear wheels off the ground and when one wheel is turned the other turns in the opposite direction and posi same situation both wheels will turn in the same direction when turned?I have read Rukee's response on many of the rear end questions I have a 10 bolt open and was interested in possibly have an auburn posi put in what should I expect to pay to have this done with all new bearings etc.. etc . From what I have read a 12 bolt chevy is the way to go but I think for the same cost or possibly even cheaper I could get the 10 bolt rebuilt with the gear I would like instead of a used 12 bolt what do you guys think.


An open rear end will just spin the 1 tire if only 1 tire is jacked off the floor and the other allowed to spin. A posi unit will spin both tires regardless if one is in the air and the other is pulling it off the jack, or 1 is on pavement and 1 is in the dirt it spins them both. A limited slip may require a bit more sudden throttle or torque, but both should spin under load. I got a rebuild bearing and shim kit with an Auburn unit from Randy's ring and pinion. Best price I could find. I've been pounding on my 10 bolt for better then 18 years with the Tri-Power and 4-speed and can't seem to hurt it. Although I did replace the carrier with the Auburn unit, I don't blame the original carrier as it had over 100k, heck as far as I know it may have 200k or 300K on it, as the speedo only reads into the 10's of thousands of miles. 10 bolts can hold their own, don't be afraid to run it! :cheers


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## geeteeohguy (Feb 2, 2008)

A stock 8.2 ten bolt open rear end converted to limited slip ( or positraction or safe-t-track or trac-loc they're all the same thing...limited slip) is a viable way to go. I've never run anything but the 8.2 stock ten bolts in all my GTO's over the years. These have all been street cars, and they were all abused in my youth. A limited slip rear end is the same as a positraction. Positraction is what Chevrolet calls it. AMC calls it Trac Loc. Pontiac, Safe-T-Track. All Limited Slip diffs have a clutch that allows some slippage so you don't drag your tires turning a tight corner. True locker rear ends do not use clutches, they use over-riding gears, etc, and are rough, jerky, and are terrible on the street. Spools are even worse....no slippage at all.


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## BearGFR (Aug 25, 2008)

"Limited slip" is a generic term - "Positrac" is Chevrolet's brand name for their "limited slip" axle, 'Safe t Trac' is Pontiac's brand name for the same thing, etc. All of them are intended to put power to both rear wheels "all the time" - sort of. An "open" or "non limited slip" axle is the one where the wheels will sping in opposite directions when you have it up on stands. It gets confusing because there are lots of different terms that all mean the same thing, like GeeTee said. And also like he said there are other types.

Is a 10 bolt strong enough? Depends on the car and how you intend to use it, actually. If you're making boatloads of torque and plan to race (either the legal or the illegal kind) then a 10 bolt isn't going to live long. 
There are 3 popular upgrades, strength wise, and all have their good and bad points. There's the 12 bolt, the Ford 9-inch, and the Dana 60. The 12 is the lightest, the Dana the heaviest - weight wise. I put the 9-inch in my 69 GTO because I didn't want to have to deal with the dreaded c-clip conundrum that comes with the 12-bolt: most sanctioning bodies require 12-bolts to have c-clip eliminator kits, but most of those kits are not recommended for street use.
Unless you need the extra strength, in your position I'd probably just rebuild the 10-bolt with a good aftermarket limited slip differential (like the Auburn) and go with it.

Bear


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## crustysack (Oct 5, 2008)

I put the auburn gear in my 65 (converting from an open rear end) and it runs great


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## trip65 (Oct 11, 2011)

i just did a rear end swap & the GTO stock rear is beefed up more than the stock lemans rear. if you look at the center of the rear the GTO the rear has an extra support on the housing and larger bushings.[
[ATTACHATTACH]12608._xfImport[/ATTACH] LeMans
]12609[/ATTACH] GTO


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## geeteeohguy (Feb 2, 2008)

trip, not sure what rear ends you are dealing with, but there is no physical difference between a stock 8.2 LeMans or Tempest rear assembly and a GTO assembly. Zero. It looks like you have two different animals posted above, not the same unit.


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