M22 ??????
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: M22 ?????? (1970LS6)
I've been told the M22, M21 and M20 can be differentiated by the numbers of rings machined into the front/input shaft. This may be an old wives tail but that's what I was told. Perhaps somebody can shed light on this one.
Per my reference, the 1970 vette was offered with either the M21 or M22 transmissions. The M21 was a no-cost option while the M22 was a $95 option.
Per my reference, the 1970 vette was offered with either the M21 or M22 transmissions. The M21 was a no-cost option while the M22 was a $95 option.
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
Re: M22 ?????? (1970LS6)
should be an identifying letter code stamped in case:
A=M20
B=M21
C=M22
or something like that. pls confirm...
and M22 has same ratios as M21, with 2.20 for 1st, but has heavier contruction and 'almost' straight helical gears
A=M20
B=M21
C=M22
or something like that. pls confirm...
and M22 has same ratios as M21, with 2.20 for 1st, but has heavier contruction and 'almost' straight helical gears
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: M22 ?????? (Turbo-Jet)
If the trans is in the car then the stamping number is what you will want to look at, which will be on the rear of the case on the right side. It should be something like P0A01C which will decode as
P=Muncie
0=1970
A=January
01= first day of month
C=M22
If the trans is out of the car then look at the rings on the input shaft. For a M22 there should be none. (but no rings does not absolutely designate a M22 as sone replacement inputs had no rings. If there are rings then it is not a M22)
The best way is to pull the side cover and look at the gears. A M22 has much straighter cut gears than a M20 or M21.
M20 or M21
M22
[Modified by Pete79L82, 9:17 PM 4/9/2002]
P=Muncie
0=1970
A=January
01= first day of month
C=M22
If the trans is out of the car then look at the rings on the input shaft. For a M22 there should be none. (but no rings does not absolutely designate a M22 as sone replacement inputs had no rings. If there are rings then it is not a M22)
The best way is to pull the side cover and look at the gears. A M22 has much straighter cut gears than a M20 or M21.
M20 or M21
M22
[Modified by Pete79L82, 9:17 PM 4/9/2002]
Racer
Joined: Jan 2001
Posts: 251
Likes: 0
From: Toronto Ontario
Re: M22 ?????? (1970LS6)
Cam has it right with the codes on the side of the case. Format of the code is P1K28C or
P=Muncie HD 4 Speed
1= model year, i.e. 1971
K=Month of production, i.e.K=July
28=Day of month produced,i.e.28th
C=2.20:1 'Rock Crusher' M-22
67Heaven has it right also that these transmission 'whine' tremendously. Easy to tell by just driving whether its and M22 or an M20/M21. This transmission, although rare and hence desireable from a collector point of view, don't generally make a good transmission for driving around.
Let us know what you find out.
P=Muncie HD 4 Speed
1= model year, i.e. 1971
K=Month of production, i.e.K=July
28=Day of month produced,i.e.28th
C=2.20:1 'Rock Crusher' M-22
67Heaven has it right also that these transmission 'whine' tremendously. Easy to tell by just driving whether its and M22 or an M20/M21. This transmission, although rare and hence desireable from a collector point of view, don't generally make a good transmission for driving around.
Let us know what you find out.
