# 3:23:1 gears



## ppurfield001 (Jan 21, 2008)

Need some help from the technical gurus. I currently have a 1967 GTO with a ten-bolt rear end. Currently running 3:90:1 gears, which causes the car to run at 3,200 RPM at 65--70 MPH. Would like to be able to cruise at those speeds at a lower RPM. My resto guys tells me that 3:23:1 gears will not fit into a ten-bolt rear and my only choices are 2:93:1 or 3:55:1 gears. I don't want to spring for a new axle and am not interested in 2:93s. Any ideas on how I could fit a set of 3:23s in my ten-bolt rear?


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## Rukee (Feb 8, 2007)

Yes, you don't need another rear end, just a different carrier. You can buy an Auburn posi unit from Randy`s Ring and Pinion that will accept the lower ratio gear sets. Give them a call with your info and what you want to do, they will fix you right up. :cheers


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## Too Many Projects (Nov 15, 2008)

To add to what Rukee stated, you can put any gear ratio in your existing 10 bolt with the CORRECT carrier. If you now have a 3 series carrier, the 3:23 would normally mount right to it, but if the 3:90's were installed on a 4 series carrier then you need a different one.

I did some research on this, as I have a GTO in my near future too, and the 3:90's were installed on a 4 series carrier, so YES, you need to buy a 3 series carrier to install the 3:23's. It is worth bringing up that my reading has also revealed that these rears have a 28 spline axle and when replacing the carrier it would be wise to upgrade to a 30 spine and new axles to benefit from the strength. You would probably want to replace the outer axle bearings at that time too, as they ride on the axle itself. 
Sequences.........think you're just gonna change one part and it's a whole series and a lot more money..


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## geeteeohguy (Feb 2, 2008)

You have what is known as a 4 series carrier. I have the same one on my '65. Your resto guy is mistaken about the 2.93 gear. You can't run one. You can run a 3.55 or a 3.36 in your present 4 series (3.90) carrier. I changed my 3.90's out for 3.36's, and it changed the car. Now it cruises at 70 plus, instead of strains. Gets a LOT better mileage, too. The best gear for a GTO in my opinion is the 3.23 you want to install. I've run them in other GTO's, and they are the best "all around" gear in my opinion. They make long trips a pleasure, and with the huge torque GTO's produce, yu don't need 3.90 gears unless you are drag racing a LOT. If I were in your shoes, I'd try to hunt down a 3.36 ring and pinion. It was the standard rear ratio for automatic cars in '67.
Jeff


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## ppurfield001 (Jan 21, 2008)

Rukee said:


> Yes, you don't need another rear end, just a different carrier. You can buy an Auburn posi unit from Randy`s Ring and Pinion that will accept the lower ratio gear sets. Give them a call with your info and what you want to do, they will fix you right up. :cheers


Thanks Jeff, Mitch and Rukee. I will follow up with my resto guy, who is trying to do the gear switch without spending more than is needed. Jeff, will 3:36s fit if I have a four-speed Muncie instead of an automatic? Regards, Paul.


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## Too Many Projects (Nov 15, 2008)

ppurfield001 said:


> Thanks Jeff, Mitch and Rukee. I will follow up with my resto guy, who is trying to do the gear switch without spending more than is needed. Jeff, will 3:36s fit if I have a four-speed Muncie instead of an automatic? Regards, Paul.


I would be EXTREMELY cautious of having a "resto" guy that didn't know the 3:23's would fit do the actual work. This is a VERY precise install that needs to be done by an experienced person, preferably an axle pro. 
The ratios are not defendant on the transmission.. Jeff was just stating that they were the standard ratio in automatic cars and therefore may be the best route to pursue. If you could hunt down an used posi carrier removed with the gears intact, it would be the most economical way to go.


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## ppurfield001 (Jan 21, 2008)

Too Many Projects said:


> I would be EXTREMELY cautious of having a "resto" guy that didn't know the 3:23's would fit do the actual work. This is a VERY precise install that needs to be done by an experienced person, preferably an axle pro.
> The ratios are not defendant on the transmission.. Jeff was just stating that they were the standard ratio in automatic cars and therefore may be the best route to pursue. If you could hunt down an used posi carrier removed with the gears intact, it would be the most economical way to go.


Thanks again, Mitch.


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## wytnyt (May 17, 2008)

Too Many Projects said:


> If you could hunt down an used posi carrier removed with the gears intact, it would be the most economical way to go


i have a set of 3.23 complete for 100
will need a pinion bearing as it has a little noise in it


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## Rukee (Feb 8, 2007)

wytnyt said:


> i have a set of 3.23 complete for 100
> will need a pinion bearing as it has a little noise in it


Isn't yours an 'open' carrier though?


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## geeteeohguy (Feb 2, 2008)

Hey LINDA!!! Did yu hear that?? A 3.23 for your GTO!


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## geeteeohguy (Feb 2, 2008)

(She's been looking for one for a while, now....)


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## wytnyt (May 17, 2008)

Rukee said:


> Isn't yours an 'open' carrier though?


yes your right
thx for clearing old age cobwebs outa my noggin


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## ppurfield001 (Jan 21, 2008)

wytnyt said:


> yes your right
> thx for clearing old age cobwebs outa my noggin


Thanks, wytnyt -- I am purchasing new equipment, but I appreciate your offer. Regards, Paul.


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## Too Many Projects (Nov 15, 2008)

wytnyt said:


> i have a set of 3.23 complete for 100
> will need a pinion bearing as it has a little noise in it





Rukee said:


> Isn't yours an 'open' carrier though?



He could still use the gears, if they don't show wear. Pull the ring gear off and trash the carrier.


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## geeteeohguy (Feb 2, 2008)

Or save the whole thing and contact Blondie67 (Linda). I think she has 410 gears in hers that she isn't too thrilled with. It could also be converted to limited slip with an Auburn unit.....waste not, want not!!!!!


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## Too Many Projects (Nov 15, 2008)

geeteeohguy said:


> Or save the whole thing and contact Blondie67 (Linda). I think she has 410 gears in hers that she isn't too thrilled with. It could also be converted to limited slip with an Auburn unit.....waste not, want not!!!!!


I wasn't aware a non-posi carrier could be converted.....:confused Must be something new from Auburn.


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## Rukee (Feb 8, 2007)

Too Many Projects said:


> I wasn't aware a non-posi carrier could be converted.....:confused Must be something new from Auburn.


It can't be converted, he just ment to put a whole posi Auburn carrier in and use his gear set. I believe anyway.


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## geeteeohguy (Feb 2, 2008)

Yes. Thanks, Rukee. I just don't like to throw anything away!!!


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## blondie67 (Jan 28, 2008)

Were you guys talking about me on the forum again? :rofl: Actually I have 3:55 gears and would've liked to go to 3:36. I believe I could just swap out the ring and pinion? My carrier is new and purchased from JEGS. I called them and they said I could only go up to 3:36 with my carrier. I just bought a set of RALLY IIs locally 15x7. Won't this help with the cruising issue?

Thanks
Linda
PS> Isn't a 2:93 an open carrier?


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## Too Many Projects (Nov 15, 2008)

Rukee said:


> It can't be converted, he just ment to put a whole posi Auburn carrier in and use his gear set. I believe anyway.





geeteeohguy said:


> Yes. Thanks, Rukee. I just don't like to throw anything away!!!


I thought wytnyt was just selling the carrier, not a complete axle, hence the "throw it away" on the carrier.


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## Rukee (Feb 8, 2007)

Yes, he has an open carrier with a ring gear attached and the matching pinion gear. So you could just use the gears.


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## 646904GTO (Feb 10, 2008)

blondie67 said:


> Were you guys talking about me on the forum again? :rofl: Actually I have 3:55 gears and would've liked to go to 3:36. I believe I could just swap out the ring and pinion? My carrier is new and purchased from JEGS. I called them and they said I could only go up to 3:36 with my carrier. I just bought a set of RALLY IIs locally 15x7. Won't this help with the cruising issue?
> 
> Thanks
> Linda
> PS> Isn't a 2:93 an open carrier?


Wether a carrier is open or not has nothing to do with the ratio. The 3.36 will bolt in and replace the 3.55 ring and pinion. If you want to go numeracally lower (3.23) you would need a carrier that fits 3.08 or 3.23. I actually has a 2.43 safe-t-track posi carrier from a 1972 Lemans in my 1964 housing running a 3.23 ratio ring and pinion. I worked at a machine shop that had CNC tooling so I measured and made a shim plate to position the ring gear closer to center so it would fit. Been in the car for 14 years now, runs great.


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## blondie67 (Jan 28, 2008)

I'm still new at the rear end thing....but I know my car came stock with an open carrier 2.93. Now it has limited slip with 3:55. I'm putting 15" tires on it and was told this would help with the freeway driving. I know I can just stick in the 3:36, but I'd rather not go 3.23 because I'd just have to swap everything out right? The whole rear end is new but I think they tightened the pinion gear too tight if that's the right terminology. There's no howling or anything, just some metal flake. Plus, try finding 3:36 gears. I actually found some just recently but wasn't prepared to pay the $600 for it. 

Linda


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## geeteeohguy (Feb 2, 2008)

Linda, a little "Metal flake" is normal in the lube during break in, but not a lot. I would drain out the gear oil when warm, and refill with fresh lube, with a limited slip additive package. If I were in your palce, having already spent the $$$ on 3:55's, I would just run a taller rear tire: about a 28 incher. Then you'll be able to cruise better. The car would probably have something like 225/75/15 on the front, and 235/75/15 on the rear, or perhaps "wider". You CAN bolt the 336 gears into your carrier, if you can get 'em. Not a big diff from the 355's, but noticeable. ALL Pontiac ratios were available in "Posi" limited slip: I've been thinking of putting in a 2:51 Safety-Track in my convertible for the heck of it...and I once spent a lot of time in a certain '67 with a 2.93 posi.....ahhhh those were the days! Get taller tires and run with it!

Jeff


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## blondie67 (Jan 28, 2008)

Hey Jeff. I appreciate your help. The car was purchased with all new rear end parts. So, I guess it was included in the 8995 price.  Everything was replaced. I had a tranny leak so I took it in to the shop and told them it was leaking above the exhaust. They ended up trying to turn the tires after looking at a brake part that was bad and couldn't turn the tires very well, so they took the cover off and found metal flake. They tried to charge me a lot to just swap it out but I settled for a magnet at this time for like stated, it is all new. They ended up replacing the pan gasket on the transmission and I took it back to the auto shop and sure enough it was still leaking in the same spot. I tell ya, doesn't anyone ever listen to a woman? The guy at the counter was even "quizzing" me on the meaning of GTO like I wouldn't own a car like this and not know the history.....hah! They never did replace the brake part. It's hard to find good help these days.....

Linda


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## geeteeohguy (Feb 2, 2008)

Linda, your differential would have to be WAAAAY out of specification to cause the wheels to be "hard to turn". Plus, if it were that tight, it wold most likely be howling like Howlin' Wolf. I suspect the bozo's at the shop have your rear brake shoes too tightly adjusted. Really common. Also, all brake parts for your '67 are available from NAPA for cheap. You can do it yourself. Way esier than putting the roof on! We can walk you through it. Common leaks on a T400 like ours is at themodulator (above the pan), and the usual one is the dipstick tube o-ring. Clean everything off with brake cleaner, drive the car, and get a good flashlight and look. You'll find it. It's just a pain in the ###. Nothing on these cars is complicated. Some systems take special tools and procedures (like valve grinding, etc.), but the majority of the operational components, YOU can maintain and repair. I believe in you, and I know the others on this forum feel the same. Don't let morons in the industry drain you of your money and time due to their own incompetence. Check that dipstick tube....that's where MINE is leaking from (again!)....
jeff


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## Rukee (Feb 8, 2007)

They prolly just have one tire off the ground trying to turn the whole posi unit. Maroons.


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## Too Many Projects (Nov 15, 2008)

Rukee said:


> They prolly just have one tire off the ground trying to turn the whole posi unit. Maroons.


 Morons


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## geeteeohguy (Feb 2, 2008)

I think Rukee was doing the Bugs Bunny thing from the classic, extremely violent 1940s Loony Tunes.....I have a co-worker who's a Vietnam vet and a funny guy who uses "Maroon" in lieu of Moron. I think it adds flair!!! But then again, it may be some sly, referenced humor that only the '65 guys understand.....
Jeff


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## blondie67 (Jan 28, 2008)

Hey now, I'm a 67 child and I remember watching those extremely violent cartoons myself. :lol: Didn't affect me any...I actually understood Rukee's maroon statement. Hmmm...what does that tell me? I agree, it adds flair.


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