T90 vs T150

These are both 3 speeds, and I'd like to keep my Jeep a 3 speed. For some reason I just like the 3 speeds.

I was wondering if the T150 can be swapped in since it's a heavier duty trans, and what would I have to change to make it fit.

On the engine side I have a Ford 351 Windsor with an unknown adapter for the T90. The input shaft is huge, and I think the engine is just too much power for the transmission. I'm on my 3rd rebuild in 2 years.

For the transfer case I have the Model 18. Will the transfer case bolt right on, and will I have to change the output shaft gear?

Thanks for any and all help.

 

The T-150 will only fit the Dana 20. The T-150 has a special output gear with a lip included for a seal. The Dana 18 and Dana 20 output gears are different, and will only mesh with their own. Unlike the Borg-Warner 3-speeds, the T-150 does not share oil with the transfer case, thus the seal between the cases.

There's been some discussion about whether you could use the Dana 18 output gear on the T-150 and let them share oil - the splines are ok. I don't recall the conclusion, but I think there's some difficulty with that. Search for the thread and you can learn more.

The T-15 will work if you can adapt it to your engine. It has about the same ratios as the T-150, and is stronger. I think the stickout is longer than the T-150, so you might be able to make a plate adapter that would work.

 

Bill Just swap in a T-18 behind that 351, If you like your 3 speed you will love a 4 speed trust me!

 

Will my transfer case bolt up to the T18?

I would need to have everything ready for this in advance, because as you know, my Jeep is my daily driver, so I can't afford to have it out of commission for more than a weekend.

 

Doubtful you could do a 4-speed swap in a weekend without practice. You'll need to change the length of the driveshafts and make new floorboards to accomodate the larger transmission, as well as connecting the components and mounting them in the chassis.

To do it, you'd have to either buy a Jeep T-18 and adapt it to your engine, or buy a Ford T-18 and adapt it to your transfer case. The only bolt-in junkyard solution that I know of is the '77-79 T-18 from a CJ, which I think will bolt up to a Ford engine. They are scarce though.

This has been discussed a lot in the past - lots of older posts both here and in the intermediate forum.

 

Ok, thanks Tim :tea:

 

Bill the bummer of it is I just missed a t-18 out of a 79 Jeep for $80 It was on craigslist in allentown came with an extra case as well. It was only on there for a few hours.