transmission input shaft

[dat]

what is the original gear tooth on the input shafts, my worn out one is an 18 tooth and I see a lot of replacements are 16.

I'm guessing that the input needs to be matched to the countershaft, or will either the 16 or 18 fit with a 33 tooth countershaft?

[Quebec Jeep]

Hey! I removed it from the FAQ section but we could move it also.

For your answer;

Look here; http://cj3b.info/Tech/T90Variations.html

'The T-90 used from 1946 to 1962 with the L and F-head four-cylinder engines is designated as the T90A1. These versions all feature top shifters, a seven inch input shaft (stick-out length) with 15/16ths inch, 10 splines and a felt-sealed front bearing retainer assembly. The input shaft has an 18-tooth, helically cut input gear. The cluster gear has a 33-tooth driven gear, resulting in a 2.98:1 first gear and a 1.66:1 second gear.

[dat]

THANK YOU
 that helped a lot

[dat]

will the 16 tooth trans input fit in where the 18 was?� or will the gear mesh be off,� I know you can change the 33 tooth cluster to a 35 tooth cluster with no trouble, but there is a lot more area to fit in the 2 teeth difference,� �on the input shaft there isn't much room to add or subtract teeth without changing the gear mesh, or will it work ok.

I kinda like the idea of a lower 1st

[dat]

Even though it won't be original, my case is a t90 A. which has 18 input and 33 tooth countershaft teeth
kinda wondering if the case is the same on a t90 c or if I can put in the 16 tooth input and 35 tooth countershaft from a t90 c in the t90 a

T-90A1
'The T-90 used from 1946 to 1962 with the L and F-head four-cylinder engines is designated as the T90A1. These versions all feature top shifters, a seven inch input shaft (stick-out length) with 15/16ths inch, 10 splines and a felt-sealed front bearing retainer assembly. The input shaft has an 18-tooth, helically cut input gear. The cluster gear has a 33-tooth driven gear, resulting in a 2.98:1 first gear and a 1.66:1 second gear.

T-90C
'The T-90 used from used from 1963 to 1971 with the F-head four-cylinder engine is designated as the T-90C. It features top shifters, a seven inch input shaft (stick-out length) with 15/16ths inch, 10 splines and a felt-sealed front bearing retainer assembly. Since the T-90C uses a case marked 'T90A,� you will need assurance that the transmission in question came from a post '62 Jeep, or you will need to pull the top cover and count teeth. The T-90C has a 16-tooth, helically cut input gear. The cluster gear has a 35-tooth driven gear, resulting in a 3.44:1 first gear and a 1.85:1 second gear.

[Carls_jeep]

If you change the input shaft to a different tooth count you need to change the counter shaft as well. They should fit into your case.

[dat]

thanks,
I was hoping that it would fit, I found a NOS input shaft and countershaft, have not bought yet, already got a NOS main shaft.  new input and countershafts are the 16 and 35 but still kinda looking for the original 18 and 33 just to keep original.  not sure which way is the best way for spending the cash

[dat]

OK, went with original 18 tooth input and 33 tooth countershaft,  I figured with 5.38 diff, that should be plenty low

[Mike S]

T-90C
'The T-90 used from used from 1963 to 1971 with the F-head four-cylinder engine is designated as the T-90C. It features top shifters, a seven inch input shaft (stick-out length) with 15/16ths inch, 10 splines and a felt-sealed front bearing retainer assembly. Since the T-90C uses a case marked 'T90A,� you will need assurance that the transmission in question came from a post '62 Jeep, or you will need to pull the top cover and count teeth. The T-90C has a 16-tooth, helically cut input gear. The cluster gear has a 35-tooth driven gear, resulting in a 3.44:1 first gear and a 1.85:1 second gear.

I changed my T90-A1 to T90C gears. You need a new cluster and main input shaft, as the gears are different. Case is the same. Herm has the gear sets.

[Carls_jeep]

Going lower may help if you going to do some rock climbing.