Short TC2000 with 5.9/MT643 and Airbrakes?

[bus-bro]

The AT545 mates to a SAE3 bellhousing, the MT643 to a SAE2. You'd also need to find that piece that fits your engine to swap trannies.

[Jarlaxle]

I drove a 1998.5 TC1000 with an MT643 behind a 175HP Cummins ISB. It was NOT a skoolie, was a "TranShuttle", originally set up as a WC bus. It had rear air ride, full air brakes, GVWR 25,000 (10,700F/15,000R), and 265/70R19.5 tires. It also had a completely flat floor inside.