# My Transmission Exploded, Need a New One and Some Advice.



## Goatman455 (May 29, 2009)

So my issue with the grinding noise was actually an exploded transmission. It's about the same cost to get a new one as to pay someone to rebuild it for me, so that's the route I am going.


I have located an M-22 and I can get either a wide ratio or a close ratio.

I am not sure what to do, the wide ratios first gear is attractive, but at the same time, my 455 built for low-end torque should be able to handle either ratio. 

What do you guys think is the best bet, wide or close ratio?

Also is the "Supercase" worth the extra couple hundred bucks?

I also could go with a 5 or 6 speed, but there is something about having the original style 4 speed in the old car. I feel like putting a 5 or 6 speed in the car is almost as bad as putting in a Chevy motor.

Of course, I do keep my options open, so if anyone has any advice on which tranny to get I would greatly appreciate it. Also, don't forget about the wide ratio vs. close ratio thing as I may just end up getting the M-22 

Thanks


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## Rukee (Feb 8, 2007)

I like the wide ratio myself, and if I could get a 5 speed and keep the factory looking Hurst shifter, I think I would do it.


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## geeteeohguy (Feb 2, 2008)

Go with a wide ratio trans. Even with the 455's torque, the wide ratio trans is better. No need for the tight gear spacing and lazy first gear ratio of the close ratio boxes. These are better suited to a high revving engine and a 3.90-4.33 gear out back. Yes, I would go with the HD midplate. You need all the strength you can get. There are a couple of threads about Muncies on this site and on the pyforums. You can get a brand new M=22 for about $1750. Congrats on keeping the 4 speed and the Hurst shifter. That's what I would do myself. Good luck.


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## ALKYGTO (Mar 29, 2010)

What rear gear? 

How is she on the highway? 

If your happy with the performance of the 4 speed I would replace it with another 4 speed. 

The TKO 5 speed has ratios very close to the M 22 but with a .86 OD. I have 4:11's and the OD tames them down nicely.


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## freethinker (Nov 14, 2009)

agree. wide ratio. if you didnt break the case i would just fix the old one. cluster gears are available new now. i could probably rebiuld it for 300-400 in parts.


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## jetstang (Nov 5, 2008)

Wide ratio and a big gear would make 1st gear worthless, both end up at 1-1 final drive ratio, with a low gear, 3.23 or less, then wide ratio would make it haul out of the hole.
I would do the 5 speed w/OD, then you can have the quick/high gear and still cruise at 80. OD is the only way to go, and just get an original looking 5 sp shifter.


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## Eric Animal (Oct 28, 2007)

Check out my buddies website Medatronics Corporation's 5 Speed Home page! Paul wrote the book (literally), on manual Muncie trannies. He also has a "Show us your broken parts" pic page!!! Eric P.S. I'd go wide ratio $.02 :cheers Talk to Paul there 561-743-5600 he will set you up.


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## facn8me (Jul 30, 2011)

My opinion.... If they built your car "today" it would have a 6 speed in it.... For a reason..... If you have a driver... why not use this misfortune to make it MORE drivable? If it's an investment go back to 4 speed.


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## geeteeohguy (Feb 2, 2008)

And if they built his car today it would have selective cylinder cut out at cruise, 7 air bags, and electronic traction control. It would have On Star and a gray plastic interior. Just sayin'..................I like a 4 speed and Hurst in a vintage GTO, but can not argue about the practicality of an overdrive trans. A 6 speed is not needed for a Pontiac, IMO, though....better suited to a low torque Chevy. That said, I'm keeping my 4 speed, and hope Goatman does the same..........


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## Goatman455 (May 29, 2009)

This is a bit embarrassing but I forget the exact ratio, it's somewhere in the 3.2-3.4 range. What were normal stock gears for a 4 speed in 69 around that ratio? If I hear it I can probably remember.


That is what is making me think wide ratio, because I don't have super short gears (rear that is) so I am thinking the shorter 1-3 might be more fun. 


For sure my old first was really long, but nothing a 455 Pontiac couldn't handle


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## ALKYGTO (Mar 29, 2010)

If it's a non A/C car it probably has a 3:55 which is about an ideal gear for these cars wieght and power wise.


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## Goatman455 (May 29, 2009)

ALKYGTO said:


> If it's a non A/C car it probably has a 3:55 which is about an ideal gear for these cars wieght and power wise.


It is a non-AC car, so with a 3.55 you recommend wide ratio?


Oh yeah, what about that supercase, and where can I pick one up for 1750? Supercases seem to sell for 2050 or so.


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## freethinker (Nov 14, 2009)

Goatman455 said:


> It is a non-AC car, so with a 3.55 you recommend wide ratio?
> 
> 
> Oh yeah, what about that supercase, and where can I pick one up for 1750? Supercases seem to sell for 2050 or so.


the supercase seems like overkill for the street but if you havent learned your lesson about sliding your foot off the clutch it might come in handy.


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## ALKYGTO (Mar 29, 2010)

Goatman455 said:


> It is a non-AC car, so with a 3.55 you recommend wide ratio?
> 
> 
> Oh yeah, what about that supercase, and where can I pick one up for 1750? Supercases seem to sell for 2050 or so.


Yes, wide ratio. before I bought my 5 speed I had 4 Muncies sitting on the shelf "just in case" and I never needed them. And that's with *750 rwhp* . Of course I never launched it on slicks and granny shifted it but I made my M-21 live for 4 years behind this motor. 

I'd personally save my money on the supercase unless you are doing some class racing which requires a "stock" tranny or you are putting out over 500 hp at the crank and regularly punish the slicks at the track. :cheers


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## 68raGTOp (Sep 4, 2011)

just my 2 cents....I bet your car is sporting a 3.36 rear. Go with a 4 speed and the wide ratio. Again my 2 cents.


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## freethinker (Nov 14, 2009)

ALKYGTO said:


> Yes, wide ratio. before I bought my 5 speed I had 4 Muncies sitting on the shelf "just in case" and I never needed them. And that's with *750 rwhp* . Of course I never launched it on slicks and granny shifted it but I made my M-21 live for 4 years behind this motor.
> 
> I'd personally save my money on the supercase unless you are doing some class racing which requires a "stock" tranny or you are putting out over 500 hp at the crank and regularly punish the slicks at the track. :cheers


street tires are harder on a trans than wrinkle wall slicks. its the shock load that kills them. a good sized street tire with the weight of other passengers in the car will mean there is no give. wrinkle wall slicks have a cushioning effect on the driveline.

i would make sure i pulled the clutch and checked the pilot bearing too. the pilot bearing gone is responsible for a lot of muncie deaths. the pilot bearing holds the input shaft centered in the trans. if its bad it allows the input shaft to deflect away from the cluster gear causing failure.


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## geeteeohguy (Feb 2, 2008)

Goatman, the muncie m22 listed for 1750 is at Rebuilt manual transmissions, transmission parts. They are in Washington state. Got a bunch of parts from them last year and the service and quality was excellent. Your '69 goat could have come with a 3.23, 3.36, or 3.55 gear. All would work much better with a wide ratio trans. Up thru '66, the standard rear ratio was 3.23 on the GTO. That changed in '67, when the 3.36 became the standard ratio, to keep up with the car's ever-increasing weight. They wanted the car to feel the same, so they wnt with a little stiffer gearing. Your '69 probably has a 3.36 cog, which is a good ratio for a stick car. If you run 27.5 inch tires (like I'm doing on my 3.36 '65 GTO) you'll effectively have a 3.23 final ratio....which is about ideal.


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## Eric Animal (Oct 28, 2007)

Call Paull at Medatronics........:willy:


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## Goatman455 (May 29, 2009)

freethinker said:


> the supercase seems like overkill for the street but if you havent learned your lesson about sliding your foot off the clutch it might come in handy.



Hahaha, you act like dumping the clutch at 1/2 throttle (really 1/3 b/c I have a spread bore carb) at 3-3.5k SHOULD blow a tranny out.


Come on, it's a muscle car, they were known to be able to burnout with regularity, a simple rolling burnout shouldn't destroy a transmission.


"If you are going to continue to peel out in your 455 GTO, you better get that supercase", haha.



What amount of power would I need to put out to make the supercase worth it? I would hate to blow out another transmission but something tells me an M-22 should hold.


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## Rukee (Feb 8, 2007)

I do burn-outs all the time, but I don't side step the clutch. Pretty much do them like my videos in my sig.


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## ALKYGTO (Mar 29, 2010)

freethinker said:


> street tires are harder on a trans than wrinkle wall slicks. its the shock load that kills them. a good sized street tire with the weight of other passengers in the car will mean there is no give. wrinkle wall slicks have a cushioning effect on the driveline.


 Really?


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## geeteeohguy (Feb 2, 2008)

Yeah, I don't buy it 100% either. Wrinkle wall slicks HOOK. Street tires spin. Spinning tires bleed off stress and shock. When you hook, you start to break things. Breaking traction tends to break less parts.


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## freethinker (Nov 14, 2009)

ALKYGTO said:


> Really?


yes really. it has to do with the instantaneous shock load and the cushion effect that the wrinkle wall in slicks have. what happens on a slick is the side wall twists and winds up like a clock spring cushioning the impact out of the drive train on launch then it unwinds and slingshots you forward 

a wide street radial deflects very little and in the case of some shorter side wall ones almost none so the drive line takes the full impact.


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## Rukee (Feb 8, 2007)

Wrinkle walls totally absorb more drive line shock then a passenger tire.


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## ALKYGTO (Mar 29, 2010)

Sure. 

I'm not even gonna dignify this with an argument. :lol:

This is why TF cars run Atlas Bucrons. :rofl:


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## Rukee (Feb 8, 2007)

Here is a good read for you....
Slicks or Street Tires: keeping drivelines alive - Wheel and Tire Forum - j-body.org - the jbody organization


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## geeteeohguy (Feb 2, 2008)

Well, THAT pretty much sheds some light on the subject. Good read, Ruk!


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## ALKYGTO (Mar 29, 2010)

The day I defer to the J body forum for information I might as well just give up.  :lol:


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## Rukee (Feb 8, 2007)

Just google "wrinkle wall tires absorb driveline shock" there are plenty of other sources that say the same thing.


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## Goatman455 (May 29, 2009)

Rukee said:


> I do burn-outs all the time, but I don't side step the clutch. Pretty much do them like my videos in my sig.




You have a secret technique, looks like a clutch dump to me?


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## Rukee (Feb 8, 2007)

Goatman455 said:


> You have a secret technique, looks like a clutch dump to me?


Pretty much let it out quickly after getting some revs, but I don't side step the clutch!


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