T-90 TRANSMISSION

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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Joe Gopan
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T-90 TRANSMISSION

Post by Joe Gopan » Sun Jan 04, 2015 6:56 am

The T-90 Transmission from the 50's-60's 6-226 powered JEEP Trucks and Wagons can be installed in the M-38 and M-38A1 by installing the shorter 4 Cyl. Main Drive Gear.
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Marty, SoCal
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Re: T-90 TRANSMISSION

Post by Marty, SoCal » Sun Jan 04, 2015 7:01 pm

In the old days it was common to install the Jeep Wagon input shaft when swapping to a V6 or V8 to make up for the adapter plate thickness. If converting back to stock, you can reinstall the original shaft into the T90 and be good to go!
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Re: T-90 TRANSMISSION

Post by Trojan » Sun Feb 22, 2015 10:42 am

I am new to this forum and starting a restoration project of a '42 Ford Script GPW. Currently the Jeep has a T84 trans and I have also acquired a T90 trans.
I am wondering if it is advisable and worth while to swap it out while doing the frame-off restoration. I have done a little research on the subject and have
determined that I may have to change out the main shaft to a shorter one (not sure which shaft it currently has.) I intend to do an overhaul of one or the
other anyway. Also, I understand that the T90 is a little taller than the T84 and the floor board would need to be modified or the cross member holding the
trans mount can be lowered a bit to make it fit with out molesting the floor board. Any thoughts or suggestions would be greatly appreciated.

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Re: T-90 TRANSMISSION

Post by gearhead » Sun Feb 22, 2015 11:19 am

Trojan, the T-90 is stronger.
It is also deeper, taller, and longer.
Cross-member must be dropped moved back or modified, or a combination.
Then your drive shafts will be wrong, rear needs shortened and front lengthened. (you want to find CJ shafts or cut your originals?)
Some have run original shafts, but the are not right.
And the clutch pivot shaft needs moved and linkage needs modified.

The other option is to notch the cross-member modify the mount and just move the engine closer to the radiator so the drive shafts work.
Either option the floor will need to be modified.

If your have the complete set up with the T-84, I would suggest rebuild it and save the hassle of the modifications.
AN original driveline is way cooler in my opinion.

If you want to do this, OK, we here on the "G" will get you through.

Ed S :)
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Trojan
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Re: T-90 TRANSMISSION

Post by Trojan » Sun Feb 22, 2015 12:41 pm

Gearhead, Thanks for your input. It sounds a little more complicated than I was originally led to believe.
I'm inclined to stay with the T84.

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Re: T-90 TRANSMISSION

Post by gearhead » Sun Feb 22, 2015 1:27 pm

There is a wealth of information on rebuilding the T-84 here on the "G".
Just do a search and with the late John Barton's' post you can do it!
Careful selection and hunting of any needed parts is part of the "fun"!

The T-84 is light duty, but with some good information and driving habits it can be a fine transmission.

Ed S :)
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