M21/M22 trans differance?
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: M21/M22 trans differance? (stingraynick75)
Try here http://www.5speeds.com go to the Muncie 4 speed section..
[Modified by bluevetteman, 5:48 AM 8/13/2003]
[Modified by bluevetteman, 5:48 AM 8/13/2003]
Thread Starter
Racer
Joined: Mar 2001
Posts: 326
Likes: 44
From: Newberg,Oregon,U.S.A.
Re: M21/M22 trans differance? (bluevetteman)
Thanx bluevetteman...here is a quote from that site....."Please note that there are 7 different Muncie input shafts. All 26 spline inputs came with 32 spline output shafts and all 10 spline inputs came with 27 spline output shafts. A common mistake is thinking that all "fine spline" 26 spline input shafts are M22 heavy duty types. This is not true. An M22 gearbox has a 20 degree helix angle on the gearset as opposed to a 45 degree angle. Also M22 gear sets were of a higher nickel alloy. The straighter angle was designed to produce less end loading of the gear train and less heat but created more noise, thus the nickname "rockcrusher". The higher nickel alloy allowed for more impact of the gears. Another misconception is if you have a drain plug you have an M22. Again this was only true when the first M22 boxes were created. But all 3925661 castings had drain plugs."
:cheers:
:cheers:
Senior Member since 1492
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
Re: M21/M22 trans differance? (stingraynick75)
There's a pic at my site below of the M-22 I'll use. It has a 10 spline input. It's been sitting in my garage since Jan and can't remember if it has a drain plug.
Melting Slicks
Joined: Apr 2000
Posts: 3,286
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From: San Jose California
Re: M21/M22 trans differance? (stingraynick75)
The angle on the gears is a very important key to strength AND power. The greater the gear angle, the more energy is consumed trying to push the gears sideways. Non synchro racing transmissions have straight cut gears. Richmond used to make one with the 5 speed.
To illustrate the point, when I did my chassis dyno I used 6th gear and made about 465-470 rwhp. I then tried 4th gear and made 483rwhp. The reason is that the ROD 6 speed uses the more shallow M22 angle for the first 5 gears and then uses an approximately 45 degree angle for 6th for quiet cruising operation. This is also why the od gear is more prone to failure with high torque ingines.
Chuck
To illustrate the point, when I did my chassis dyno I used 6th gear and made about 465-470 rwhp. I then tried 4th gear and made 483rwhp. The reason is that the ROD 6 speed uses the more shallow M22 angle for the first 5 gears and then uses an approximately 45 degree angle for 6th for quiet cruising operation. This is also why the od gear is more prone to failure with high torque ingines.
Chuck
Safety Car
Joined: Jun 2002
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From: Pearland TX
St. Jude Contributor
Re: M21/M22 trans differance? (Chuck Harmon)
Thanks for posting the discussion guys. I've been looking for identification #'s that I *should* find on my '71. From what I saw I the casting # should be 3925661 and if it is in fact a M-22 it should have #'s P1(month A-K)(date)C.
With "C" designating M-22. Correct? Could I assume you might find an earlier year Muncie tranny in your vette? As in a P0K15C.... a '70 built on December 15 and M-22 in a early production '71 vette?
[Modified by bgrice, 12:01 PM 8/13/2003]
With "C" designating M-22. Correct? Could I assume you might find an earlier year Muncie tranny in your vette? As in a P0K15C.... a '70 built on December 15 and M-22 in a early production '71 vette?
[Modified by bgrice, 12:01 PM 8/13/2003]
