4 speed input shaft grooves

[Greg S.]

I know that the number of grooves is supposed to indicate the first gear ratio, maybe other gears also. I can't find any info on what is what. The transmission in the picture is a January build 76 super T10 with three rings on the input shaft. Transmission is in the car so I can't turn the shaft and count the output shaft turns

Anybody know what the first gear ratio is?image.jpg

[Joe L.]

Re: 4 speed input shaft grooves

I know that the number of grooves is supposed to indicate the first gear ratio, maybe other gears also. I can't find any info on what is what. The transmission in the picture is a January build 76 super T10 with three rings on the input shaft. Transmission is in the car so I can't turn the shaft and count the output shaft turns

Anybody know what the first gear ratio is?[ATTACH=CONFIG]62688[/ATTACH]

Greg------


For the 1975-79 Super T-10, the 3 grooves on the input shaft denotes an M-20, wide ratio application. The first gear ratio for this transmission is 2.64:1.

[Greg S.]

Re: 4 speed input shaft grooves

Thank you Joe. Is there a chart somewhere that provides this information for various years?

[Joe L.]

Re: 4 speed input shaft grooves

Thank you Joe. Is there a chart somewhere that provides this information for various years?

Greg------


There may be such a chart but I'm not aware of it.

[Joe L.]

Re: 4 speed input shaft grooves

Greg-------


Here's my own table, though:


1966-74 Muncie M-20 wide ratio--------2 circumferential grooves

1966-74 Muncie M-21 close ratio--------1 circumferential groove

1966-74 Muncie M-22 HD close ratio----no circumferential grooves

1975-79 Borg Warner T-10 M-20 wide ratio-----3 circumferential grooves

1975-79 Borg Warner T-10 M-21 close ratio-----2 circumferential grooves

One caution: most, if not all, aftermarket, SERVICE gears for the above applications do not have ANY circumferential grooves regardless of the transmission type. So, if the transmission has had one of these installed, you can't identify it by this means.