# Ring and Pinion Gear for GTO



## alanmay0 (Sep 3, 2015)

My 1967 GTO was born an automatic. Some where over the past 49 years someone changed it to a 4 speed. The problem is the rear end is a 2.93 which is what came on automatics with a/c. What came on 4 speeds with a/c was a 3.23. So I would like to change mine to the 3.23. I am looking at different sites who sell the ring and pinion gears but they are talking 8.2 and 8.5. I guess this is the diameter of the ring gear. My rear end is a 10 bolt posi so what size ring and pinion would mine be? Then I believe I could order the same size in the 3.23 and it would all fit. I just don't know if I have a 8.2 or a 8.5. My car is being restored at this time so I am not able to get to it to check the size. If anyone can help I would appreciate it.
thanks
alan


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## GTOJUNIOR (Aug 7, 2011)

Quickest way to ID the 8.2 which yours would have come with has scallops on the cover Vs the 8.5 cover which is circular/round. Several vendors out there selling gears & overhaul kits.


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## Pinion head (Jan 3, 2015)

GTOJUNIOR said:


> Quickest way to ID the 8.2 which yours would have come with has scallops on the cover Vs the 8.5 cover which is circular/round. Several vendors out there selling gears & overhaul kits.


Unfortunately, the "round" cover ID scenario is not true. 
-The most common style of '71-72 8.5 A-body rear used a cutout style rear cover, as nearly a million were built, this style housing is not that rare. 
-There are two lesser common style '71-72 8.5 A body housings that use a round cover. 
-Any of the 3 styles, are the only styles of 8.5 A-body rears that will directly bolt in a '64-72 GM A-body. 

One of the easiest ways to spot a stock 8.5 housing is any 8.5 has a stock pinion flange that accepts 7/16" headed bolts which held stamped steel straps to attach the ujoint. There are other ring gear size 70's & 80's GM rears that also used the stamped steel straps, so have to be careful. All different styles of 8.2 rearends used U bolts & nuts to attach their ujoints at the pinion flange. 8.5 A-body axle tubes will be 3" in diam, same diameter as any 8.2, type "O" 10 bolt, or a 12 bolt.

Back to Alan's situation, most likely, your car has its original 8.2 PONTIAC rear. Look for the casting number on the the center housing, it will begin with a 97xxxx. Then ck the stamped 2 letter ID code on the axle tubes. If the center housing casting number, begins with a 1xxxxx, its a '68-70 BUICK 8.2, then your original rear has been swapped out. '68-70 BUICK 8.2s are their own animal, use their own specific internal parts. Desiring early 8.2 PONTIAC gears in the 3.23 ratio, they have to be sourced in nice used shape, the 3.23 8.2 PONTIAC gears have never been made by the aftermarket. Have shipped out this ratio of 8.2 PONTIAC gear set many times & have more.


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## GTOJUNIOR (Aug 7, 2011)

That's what I was afraid of. 
I had to dig in my files and sure enough I did secure an excellent USED set of 3:23 gears to use.
Sorry for any misdirection.


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## alanmay0 (Sep 3, 2015)

Thanks for all the information. So then more likely than not I have the 8.2 gear. My casting does start with a 97 and I can't check the other stamping at this time. So you say no one produces the 3.23 in the 8.2 so where can I get a set of rack and pinion gears then??? Any suggestions will be welcome.
thanks
alan


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## Swany 48 (Sep 30, 2017)

where can i get a 8.2 ring gear spacer so i can install a after market set of 3.73 gears on my 3.23 carrier? any help would be appreciated. [email protected]


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## 67Mac (Jun 16, 2021)

Pinion head said:


> Unfortunately, the "round" cover ID scenario is not true.
> -The most common style of '71-72 8.5 A-body rear used a cutout style rear cover, as nearly a million were built, this style housing is not that rare.
> -There are two lesser common style '71-72 8.5 A body housings that use a round cover.
> -Any of the 3 styles, are the only styles of 8.5 A-body rears that will directly bolt in a '64-72 GM A-body.
> ...


Looking for a ring and pinion set in 2.90-3.23 range for my 67 LeMans. Planning on upgrading to the Auburn GripNLoc. Thanks


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## 1968gto421 (Mar 28, 2014)

Alan, Probably your best bet for a 3.23 ring & pinion would be to check with Pinion Head (post #3) as he is a member here and has alot of parts. If Pinion Head is unable to assist you, try *Frank's* *Pontiac parts*. He has a vast number of used parts and members here and on the PY forum have recommended him to me.



https://www.frankspontiacparts.com/aboutus.htm





https://www.frankspontiacparts.com/usedparts/gtoparts.htm


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## 67Mac (Jun 16, 2021)

67Mac said:


> Looking for a ring and pinion set in 2.90-3.23 range for my 67 LeMans. Planning on upgrading to the Auburn GripNLoc. Thanks


Thanks, I will check it out.


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## 67Mac (Jun 16, 2021)

Pinion head said:


> Unfortunately, the "round" cover ID scenario is not true.
> -The most common style of '71-72 8.5 A-body rear used a cutout style rear cover, as nearly a million were built, this style housing is not that rare.
> -There are two lesser common style '71-72 8.5 A body housings that use a round cover.
> -Any of the 3 styles, are the only styles of 8.5 A-body rears that will directly bolt in a '64-72 GM A-body.
> ...


Looking for a ring and pinion set in 2.90-3.23 range for my 67 LeMans. Planning on upgrading to the Auburn GripNLoc. Thanks


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## LATECH (Jul 18, 2018)

Swany 48 said:


> where can i get a 8.2 ring gear spacer so i can install a after market set of 3.73 gears on my 3.23 carrier? any help would be appreciated. [email protected]


3.73 wont work on a series 2 carrier , which is what you have. 3.08 is supposed to be the Break, but it is actually 3.23 and lower for a series 2. 
Do yourself a favor. Get a Yukon LSD 3 series and a set of 3.36 gears from YUKON. I have put a lot of gear sets in lately and it would seem that most have some kind of noise. I have installed 4 Yukon sets in the past year and they have all been silent.
The Yukon limites slip differential will set you back 5-6 bills, and it is worth every penny
Mine is very agressive and I smoke BOTH tires. It hooks well also because i have spherical joints in the adjustable control arms for the rear. Its a good working setup.
The yukon is also rebuildable. Most others are not. do your homework.
I would not get an Auburn, but that is my prefrence


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