I have a project and a spare tranny, so I must ask this question-

On an EA-81 d/r 4speed, how much torque can the transmission handle? No shock loading, just constant smooth power. What do you think would break first?

not sure how much it could take but i was told the synchros would fry first

I would think the differentials would chip first.

Basically, what I need is something to reverse the direction of power, slow the speed down, and split it 90º with a differential. I have an engine and automatic transmission, and I want to hook the output of the auto to the input of the tranny, run it in low range, in reverse, and take power off the axle stubs. The tranny will be locked in reverse, under a plate, with no linkage connected to it.

I've blown two diffs and a transfer case on three separate trannies.

Maybe I should just throw this thing together and see if it holds- it'll see some pretty decent stress on it, hoepfully the wheels will slip before it reaches the breaking point if I remember not to overload it. If/when it breaks, it'll be replaced by a Ford 9" diff with 7.30 gears, flipped upside down.