4 speed od or 5 speed

The AX15 isn't a secret, I know of at least one guy on here that used one, and several on other forums. The other transmissions to look at are the R154, AR5 or MA5. They are all of an Aisin design and bolt into a Dakota bellhousing. Rated torque is pretty low, but there are plenty of stories of these transmissions surviving just fine behind higher hp motors (an LS7 swapped Soltice, for one).