1965 Mustang BW T-10 (HEK-M) gear ratios

[awhtx]

According to mustanktek the BW T-10 (HEK-M) in my 1965 Mustang has a 2.36 1st gear. I have mine apart for rebuild and I calculate a 2.74 ratio for 1st gear. Here are the gear tooth counts (MS= mainshaft, CS= countershaft):

1st: MS 36, CS 17. 2nd gear: MS 30, CS 19. 3rd: MS 28, CS 24. 4th: MS 24, CS 31.

I calculate 2.74, 2.04, 1.51 and 1.00 ratios for 1st through 4th. I understand that 4th gear is straight through (countershaft has no effect) and for the other 3 gears I have taken into effect the countershaft. Am I calculating incorrectly?

[Asm109]

You have to factor in the gear ratio from the input shaft to the counter shaft

1st gear is (Teeth on counter shaft/teeth on input shaft)*Teeth on first gear/teeth on countershaft).

[awhtx]

Originally Posted by Asm109

You have to factor in the gear ratio from the input shaft to the counter shaft

1st gear is (Teeth on counter shaft/teeth on input shaft)*Teeth on first gear/teeth on countershaft).

I did that.
For the Mainshaft (Output shaft) to rotate 1 turn in 1st gear the 36 tooth gear must make 1 revolution which means the 17 tooth Countershaft gear must make 2.117 revolutions. When the Countershaft makes 2.117 revolutions it's 31 tooth gear turns the 24 tooth 4th gear (which is actually part of the input shaft) 2.735 revolutions which I rounded off to 2.74.
I calculate 2.74 for 1st, 2.04 for 2nd, 1.51 for 3rd and 1.00 for 4th.

[gjz30075]

Is it possible someone changed out the guts in yours? I don't know who runs Mustangtek but on the 'contact us' page there's this:

- If you spot data errors, have additional info on part numbers or descriptions feel free to submit this information.

I think Mustangtek is like the Wikipedia of Ford codes.