T90 vs T86

Just picked up a T90 trans from a CJ, it has a deeper first gear which is nice, are there any other reasons to swap it with the T86? I have always been lead to believe it is a much stronger transmission. I plan to rebuild it on the bench and swap it in later, but want to make sure it is worth my while behind the V6.

 

Technically speaking, a straight cut gear will be stronger than a bevel cut gear because of the lower lateral loading. IIRC the T-86 is basically a T-90 except that the main shaft splines spiral in the T-86 (for some reason) and the 1st gear is bevel cut in a T-86 vs. straight cut in a T-90. Straight cut gears will whine; the more bevel, the quieter the gear.

Certainly parts are easier to find for the T-90, in particular good used parts. I think the T-90 needs a long stickout like the Utility Truck to work with a V6. If this is a T-90C from a F134, it will have too short a stickout to work with a V6, and the cluster gear will not be compatible with the longer input gear you'll need.

My knowledge of the pre-AMC era is a little patchy, so I could be wrong about this, but I think you'll need the long input gear version to work with a V6.

 

This was behind an F-head... DOH!

I am sure I can come up with an input shaft if needed though, thanks guys!

I can deal with gear whine if I get a little more strength... My mom had a 66CJ5 for her first vehicle and when my parents first got married... My dad still tells the horror stories about my mom blowing the trans apart with the V6 3 times... and they didn't wheel it at all.

 

just depends on the driver and his/her driving habits.
I've run my T90 behind the V6 for over 20 years now, never had an issue with it.