4-speed ID? can you tell by the gears if its a?

[John P.]

This is my comanding officers transmission he pulled from his 55 chevy
any ideas as to its origins here are the numbers

side cover casting 3831707
top of case stamping 7K147519
Right Hand side case stamp P7T28
case casting 3885010
tail casting 3846429
and the bearing retainer casting last 3 # 020
the input shaft has 2 rings

I think this may have come from something besides a corvette
and he is looking to sell his for $300 think I should get it from him?

also about the gears on the rany I pulled from my 69 it has a 94 case and A smooth input shaft the front bearing retainer is a 69 and the tail housing is also frm 69 the gears inside are sloped at a extream angle downward is this concurent with a M-20, M-21? or M-22?

thanks
johnny

[Kevin Whiteley]

Re: 4-speed ID? can you tell by the gears if its a

Colvin's books list the 3831707 Side Cover as being used from 63-65 for various vehicle, including Corvettes. The Maincase, 3885010, is for 66-67 various vehicle, including Corvettes. The Tailhouse, 3846429, was used for 64-65 various vehicle, again, including Corvettes. The Bearing Retainer, with last 020, is 3915020, used in 68-69 various vehicles, including Corvettes.

The P7T28 decodes as P=Muncie, 7=1967 MODEL year, T28=December 28, so if I understand the system, the transmission was assembled December 28, 1966, which is during the 1967 model year.

The 7K147519 is the vehicle VIN derivative. I think it is a 1967 3-speed passenger or truck transmission. K=McKinnon plant (wherever that is) with the remaining being the vehicle number.

[Verle R.]

Re: 4-speed ID? can you tell by the gears if its a

Johnny,

side cover casting 3831707 63 thru 65
top of case stamping 7K147519 VIN derivative, 1967 in Kansas City
Right Hand side case stamp P7T28 7 is year, T look again, month code, 28th
case casting 3885010 66 - 67
tail casting 3846429 64
and the bearing retainer casting last 3 # 020
the input shaft has 2 rings M20

This a "put together" transmission with parts from several years.
I suspect it was originally installed in a 67 Chevelle in Kansas City.

Someone else should respond on your 69 question.

Verle

[Patrick T.]

Re: 4-speed ID? can you tell by the gears if its a

Below is an inside picture of an M-22 Rock Crusher. Notice the relatively straight 22 degree helical gear angle, as opposed to a 37 degree angle for a M-20 or M21.

[John P.]

Re: 4-speed ID? can you tell by the gears if its a

Thanks for the picture Patrick!

Ill have to look at the tranny tonight to verify, But The gears look to have a lot more of a downward angle than that..

thanks
johnny

[William C.]

Re: 4-speed ID? can you tell by the gears if its a

No two ring inputs were used on M-22 trans at any time.

[John P.]

Re: 4-speed ID? can you tell by the gears if its a

Bill,
Im kinda mixing up 2 questions here.
the first one was about my CO's tranny

The second about my transmission that came outof my 69, It has no rings on the output shaft and the gears are at extream downward angles.
But my tranny main case is from a 64 where my tail shaft and front bering retainer are correct for a 69.
I was hopeing I could use my co's transmission to make mine correct but it seams his is for a 67 non corvette...

thanks for the hlep!

johnny

[John P.]

Edit to original post!!!

also about the gears on the trany I pulled from my 69 it has a 1964 case and A smooth input shaft the front bearing retainer is correct for a 69 and the tail housing is also for a 69 the gears inside are sloped at a extream angle downward is this concurent with a M-20, M-21? or M-22?

thanks
johnny

[William C.]

Re: 4-speed ID? can you tell by the gears if its a

Johnny, a coarse spline no-ring trans is also a wide ratio trans. FYI the gears are interchangable between the two with the exception of the input and cluster, and by changing the side covers they will work for either year. the only real difference is the '67 had the speedo drive coming out the pass side of the tailhousing and the '64 brought it out of the drivers side, unless the '67 is from a Pontiac, as they uded the drivers side speedo takeoff for a number of years.

[Clem Z.]

Re: 4-speed ID? can you tell by the gears if its a

i understand that after market input shafts do not have any grooves on any ratio. the best bet is to put it in gead and turn the input,count the turns till you get one turn of the output. JMHO

[Kevin Whiteley]

Correction- K=Kansas City *NM*

[William C.]

Re: Edit to original post!!!

M-20, but you can count the teeth on the input shaft to be sure, 21 tooth is a '63-65 M-20, 26 Teeth is a M-21 or M-22 with the visible difference being the helix angle being greater on the M-21, 24 tooth is a '66-74 M-20

[John P.]

Re: 4-speed ID? can you tell by the gears if its a

well the input chaft has 10 splines.
it is not a rockcrusher.

and clem if its in first gear how many turns should it be 20-21 on the front shaft?

thanks

johnny

[Clem Z.]

Re: 4-speed ID? can you tell by the gears if its a

close ratio(2.20) a little less than 2 1/4 turns and the wide ratio(2.54) little bit more than 2 1/2 turns

[Larry E. Howard]

Re: Edit to original post!!!

Johnny go to wwwinterlog.com/~muncie/history.html it is all explained there. The cluster pin in your tranny should be 7/8 inch on these there were no
M-22s only M-20s(no Rings) and M-21s(one ring) When GM went to the one inch pin in 1966 then the M-20s had 2 rings, M-21 still had one ring, and M-22s had no rings. This ID continued through 1974. This is reguardless of the splines on the input or output shaft. Alot of people think the large output shaft(400 turbo yoke) is a M-22 but the truth is that shaft was used in all trannys after 1970. I have rebuilt, bought, and sold abot 50 muncies in the past 2 years, Although they say you can't tell by the rings, I have not seen one yet that could not be identified by the rings on the input shaft.
Larry