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Topic: 4 speed tranny identification

in Forum: C3 Driveline Components


4 speed tranny identification

Posted: 8/4/03 5:54pm Message 1 of 5
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JACKSONVILLE, NC - USA
Joined: 12/13/2002
Posts: 109
Vette(s): 1969 427/435 1990 ZR-1
Who is good at identifing muncies?

Im not sure what I have found in my transmission.

the gears are sloped at a extream angle downward, acording to my 69 stingray guide book this leads me to believe I have M-22 guts in my tranny.
input shaft is smooth no rings

Only problem is I have a 64 case and side cover, the tail shaft and front bearing retainer are for a 69.
I have pictures just post here and ill send them or Ill up load them and send you the link to them.....


I also have these part numbers from my comanding oficers transmission any one care to take a stab?

side cover casting 3831707
top of case stamping 7K147519
side pass side stamp P7T28
case casting 3885010
tail casting 3846429
and the bearing retainer casting last 3 # 020
the input shaft has 2 rings so its a M-21
I think this may have come from something besides a corvette

any help is appreciated!
and he is looking to sell his for $300 |headscratch| think I should get it from him?


Johnny P 69 435 HP Tri Power 90 ZR-1 SSGT U.S. MARINES |IMG| http://www.c3vr.com/member_uploads/2101_2200/2191/sig%20pic.jpg|/IMG|
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4 speed tranny identification

Posted: 8/5/03 7:31am Message 2 of 5
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KETCHIKAN, AK - USA
Joined: 2/7/2002
Posts: 86
Vette(s): 73 custom coupe stingray 4:11 rear,502 cid.
Hi Johnny, If the gears have an extereme angle cut they are most likely either M-21 or M-20 gears. The M-22 gears are cut with almost no angle to them.
The stamped number decodes as, P=Muncie, 7=1967, T28=December 28th. Here is a link to help you identify your's.
http://www.dandltransmission.com/muncieratio.html


4 speed tranny identification

Posted: 8/5/03 9:47am Message 3 of 5
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Lake Oswego, OR - USA
Joined: 12/29/2002
Posts: 355
Vette(s): 1968 Corvette T-Top Coupe, 427 L71, Rally Red Exterior, Saddle Interior
Johnny

According to the NCRS Judging Guide, the case ID should have a letter after the date. A = M-20, B = M-21 and C = M-22. The M-20 has a 2.52:1 first gear ratio. The M-21 and M-22 have a 2.20:1 ratio. My transmission case is missing the letter after the date also, so I can't explain it. This probably doesn't help much, but I have another book at home and I'll check it tonight and see if it has any more info. Will also check my Chevelle id book and compare the numbers to it.

Mark

|UPDATED|8/5/2003 9:47:52 AM|/UPDATED|



4 speed tranny identification

Posted: 8/5/03 1:39pm Message 4 of 5
Former Member
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Lake Oswego, OR - USA
Joined: 12/29/2002
Posts: 355
Vette(s): 1968 Corvette T-Top Coupe, 427 L71, Rally Red Exterior, Saddle Interior
I checked the book on Chevelle's and none of the numbers match a Chevelle, so its looking more like it may be a Vette transmission.

Mark


4 speed tranny identification

Posted: 8/5/03 1:52pm Message 5 of 5
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JACKSONVILLE, NC - USA
Joined: 12/13/2002
Posts: 109
Vette(s): 1969 427/435 1990 ZR-1
Well as far as the cut I was going off pictures so I wasnet sure about that.

But the other tranny I didnt even check my books at home last night I worked later and spent the night with the wife..
I might post the numbers at NCRS.org...

thanks guys

johnny


Johnny P 69 435 HP Tri Power 90 ZR-1 SSGT U.S. MARINES |IMG| http://www.c3vr.com/member_uploads/2101_2200/2191/sig%20pic.jpg|/IMG|

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