I've heard multiple types of auxiliary transmissions being used. Those from 490 Chevs to Model A to Warfords. I like to see or at least hear of people's unique sets ups. With pro, cons and possibly pictures.
Each of my speedsters have Muncies with the under, direct, over and reverse. Functional, but loud in all but direct, and takes practice to shift since not syncronised. My hack has (as told by the old guy who built it years ago)a Model A "double down" turned around backwards to provide a direct and overdrive that is foot actuated with a U-shaped pedal in the floor. Functional in flat land, but with the extra weight, overdrive not used much. When I got my TT, it had a FULLER AND SONS, mounted between the rear of the driveshaft and front of the differential, to provide direct and underdrive. It was actuated by a ruckstel shifter. I don't know how it performs--I removed it when I got the TT in 1976, and it's still on the shelf! I'd suggest you get a copy of "The Model T FordOwner". There's lots of ads in there for aux trans--great book.
Here is the approximately '23-24 Buick trans in my doodlebug, in between the T engine and TT rear axle. I have been told the pedals have been cut off flush with the case
Pros: I get a true neutral.
Cons: I still have no rear brakes when it is in neutral.
I haven't tried to put the Buick in reverse to see what will happen.
I have an old trans identified as late 20's Chevy where the input shaft has been machined to fit into the T trans output shaft. I might use it for a planned garden tractor project. I posted this video when I tried to identify it:
John McGinnis sent me a PDF with a good article by Louis P. Baudoin. Here is the full article including a description on how to adopt a '35-'38 Dodge, Plymouth or DeSoto transmission for a T:
Many thanks for publishing that article. Wasn't sure the best way to post. Copy and paste seemed possible, but I didn't try.
Thanks again...it may be of interest to many folks.