# Posi unit help



## Wendt69 (Jan 6, 2016)

Hey guys I have an original 8.2 with 3.23 open rear end in my 69' GTO. 

I'm in the middle of a chassis/engine rebuild and the one tire spin no traction has got to go! Seriously impossible to get traction off the line even with the 47 year old 400. 

I hear bad press about Auburn so I looked into Eatons posi unit but it's not offered for anything less than 3.55. I want to keep my 3.23 gear ratio as my engine build (which could be delayed big time cause of our embarrassing Can. dollar) will be for street driving. 

Has anyone had an Auburn installed? Results? Or is there another way?

Btw it's an original car so I plan to keep it that way. Not concours but I sure ain't putting a Ford rear in her!


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## Rukee (Feb 8, 2007)

I installed an Auburn unit, 3.55 what is what the car was born with. Been several years, no issues at all.


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## Wendt69 (Jan 6, 2016)

Good point Rukee.
My car won't be hammered on until one of those Dodge ram guys pull up to a set of lights. Lol

Who did you order yours from?

It's a good thing the Auburn is cheaper cause right now I'm paying next to $500 on every $1000 USD.


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## Rukee (Feb 8, 2007)

I believe I bought it from SUMMIT Racing.com.


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## Lemans guy (Oct 14, 2014)

Also you can check Randy's Ring and Pinion. They are a National outfit, got a location near here, lots of Auburn, Yukon, Dana,....you name it.

They have a good enough and huge mail order business, lots of off road era, and good techs....:thumbsup:


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## pjw1967 (Mar 10, 2014)

A few years ago the Muncie in my '67 gave out. Got it rebuilt. 3 weeks later my peg leg 3.23 gave out. Got a 3.55 Auburn locker. 3+ years now and no issues.


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## Wendt69 (Jan 6, 2016)

Cool. Thanks guys
PJW you say an Auburn locker? Do you mean a clutch posi unit or the locker style gears that 4x4 guys use?

If the it's posi unit then it sounds like I'm definitely going for the Auburn, hopefully there's not too many off shore parts?!? Definitely prefer Made in America but that's hard to find nowadays.


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## pjw1967 (Mar 10, 2014)

Wendt69 said:


> Cool. Thanks guys
> PJW you say an Auburn locker? Do you mean a clutch posi unit or the locker style gears that 4x4 guys use?
> 
> If the it's posi unit then it sounds like I'm definitely going for the Auburn, hopefully there's not too many off shore parts?!? Definitely prefer Made in America but that's hard to find nowadays.


Locker was how the shop described it but it's likely just a posi. Let me dig out the receipt.


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## Pinion head (Jan 3, 2015)

When the Eaton 8.2 Pontiac carriers were introduced in the early 00's, there was a mid ratio (2.93-3.08-3.23) carrier, and a low ratio (3.36-5.57) carrier. Unfortunately, over the last 4-5 years, it's been near impossible to come up with an Eaton Pontiac 8.2 carrier in the mid ratio design. Over the years I've ordered several of the Eaton 8.2's along with several of the Auburn Pro Series Pontiac 8.2 carriers. Nearly all were installed in nodular 8.2 Pontiac 10 bolts. Both are a better design if the nodular 8.2 is getting hammered on. Short of that abuse, one can get by with the standard Auburn cone type carrier.

In a position, where Pontiac 8.2 center housing is just a std gray iron 8.2, the sealed bearing axles need replacing, and one is interested in swapping in a posi and/ or gears for a performance build, blowing the bank on building up the gray iron 8.2 is a total waste of funds. Much easier and less expensive to have a HD 8.5 A body rear built.


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## Rukee (Feb 8, 2007)

Doesn't the locker for the 4x4's have a wire going to them that the driver can flip a switch and "lock" the rear/front diffs into posi?


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## Pinion head (Jan 3, 2015)

Many late model 4x4 pickups use an electrically activated locker mfg by Eaton. Have never installed one. 
From '71 up through the '90's GM pickups typically had a governor lock Eaton Posi, if the truck was factory equipped with a posi. The Govloks are far from a performance piece. Add taller wider tires and go play hard in the mud, and you will wish you didn't when you find out what it cost to replace the rearend.

Back to Pontiac 8.2's, there are no lockers avail for the Pontiac 8.2 10 bolt. locking up the rear should be no problem with a good tight posi. All the different 8.2 10 bolts eventual weakness is the lack of pinion support.


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## Wendt69 (Jan 6, 2016)

Appreciate your responses, Pinion head I heard the 8.5 is extremely rare?

If I installed a new Auburn posi unit, used my existing gears but replaced bearings ( be it that all this work will be done by someone much more qualified than me) am I still asking for trouble? 

The car has 58,000 miles. 

Thanks guys.


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## PontiacJim (Dec 29, 2012)

Wendt69 said:


> Appreciate your responses, Pinion head I heard the 8.5 is extremely rare?
> 
> If I installed a new Auburn posi unit, used my existing gears but replaced bearings ( be it that all this work will be done by someone much more qualified than me) am I still asking for trouble?
> 
> ...



Pinion head has covered the 8.5 rear and the 8.2, both the differences and the advantages of the much better 8.5. However, the real question is how do you plan on driving the car? An automatic car is also a bit easier on a rear end than the slam-bang of a manual trans.

The 8.2 holds up well under most conditions until you start going higher HP above factory specs, wider & stickier tires, or plan on beating on it like a red-headed step child - like I do, but never lunched one either. The 8.5 should not be too difficult to find. I find them on the local Craigslist on occasion for a reasonable price as well, $100-$150.

At 58,000 miles the gears may be in great shape or a little worn depending on how it was driven. I would make that decision once your differential guy tears it apart and gives it an inspection, and maybe even take the gears to a machine shop and ask them to magnaflux them for cracks which you might not see with the naked eye - cheap insurance. 

Do a search through the forums on the 8.5 and you may get a little more info on them and what to look for. :thumbsup:


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## Wendt69 (Jan 6, 2016)

Appreciate that Jim, it's an auto trans.

I was planning on a stroker build but after disassembly of the engine we noted the great condition of the bearings and especially the crank journals, I'm keeping it a 400 the engine builder may bore it out .30 over with new rods, pistons, rebuild the 62 heads new cam roller/tappet?!? Etc. 
anyway probably I will end up around the 375-400 hp range. 

I'll take your advice and open it up and see what we have, hopefully it's not a peek and shriek! This is a journey of surprises. 

Great insight guys!! Thanks.


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## stoney200gto (Jan 23, 2016)

*stoney200gto*

You probably have a borg warner posi and put bigger tires on your car than it came with. that unit cant handle that, but the good news is it is not blown and it can be repaired.I repaired mine and you can find the repair procedure on u tube. both of the other replacement units will work with 3.55 gears according to tom's ring and pinion.com


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## Wendt69 (Jan 6, 2016)

Well I got the rear diff out last night and I'll get it off to be inspected for possible rebuild. 

Is this why one tire spins when I hammer on it? Lol

WF code is 3.23 open auto trans. According to the Wallace racing site.


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## Rukee (Feb 8, 2007)

Just weld the spider gears together. 
j/k


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## crustysack (Oct 5, 2008)

I went with the Eaton unit, and new yukon ring and pinion gears, No problems what so ever and I have dropped a few hot suppers on her.


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## Wendt69 (Jan 6, 2016)

Not a bad idea Rukee! lol

"dropped a few hot suppers on her" Love it!

Its likely I'll keep the existing rear end and install a posi, It's important to me to keep the originality as much as possible. I am having the engine rebuilt and the TH400 is being rebuilt as I write this. I'm not doing anything to heavy duty so I'm confident the rear will hold up fine. At 42 my foot is much softer, I had a 72 Lemans in high school and beat the living sh!$ outta that thing! man it was a beast. It actually had a chev 350 because it was a Canadian model, my buds and I rebuilt the motor in grade 12 automotives class.

Everything will be fine until one of those Dodge guys pulls up beside me! then my blood boils and its on! And after that I'll be on here asking if anyone has an 8.5 for sale. lol


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## pjw1967 (Mar 10, 2014)

Wendt69 said:


> Cool. Thanks guys
> PJW you say an Auburn locker? Do you mean a clutch posi unit or the locker style gears that 4x4 guys use?
> 
> If the it's posi unit then it sounds like I'm definitely going for the Auburn, hopefully there's not too many off shore parts?!? Definitely prefer Made in America but that's hard to find nowadays.


Found the receipt (2009) but all it shows is Auburn posi unit with 3:55 gears. My mistake for calling it a locker. In any event we now know it is in service 6+ years with no issues. I'm guessing 8k miles. BTW, I seem to remember that it takes special fluid. Anyone who can guide me here? Thanks.


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## PontiacJim (Dec 29, 2012)

Wendt69 said:


> At 42 my foot is much softer. lol



Ya, OK, who you trying to BS? At 56 my foot, my brain, and my....... hasn't gotten softer. 

When one of the Dodge guys, Chevy guys, Ford guys, Import guys, Hot Rod guys, or motorcycle guys pulls up along side it will be on and you know it. Liar, Liar, pants on fire. Your foot is goin' down and you know it. :yesnod:


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## Wendt69 (Jan 6, 2016)

^ Ha ha ha! ^

Thanks PJW, really appreciate that. 

Pontiac Jim... Man I think you are correct! It's not likely I'm going to be driving Miss Daisey around after she's all rebuilt I ain't foolin' no one.


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