HI Jim, Sorry, No experience with the AX15 5spds, Other than what I read On Offroad.com
Which says that its a medium duty type, and has an all aluminum case. From what i have heard and seen from a Frineds 258 Backed by a T-4 and T-176 they are older simpler and Tougher than a bag of hammers. Offroad has a Good section on AMC/Jeep Transmissions, autos and sticks. Though the T-4/5 are technically light duty units they are rugged Plentiful and they have a tight smooth pattern. Mustangs with all kinds of motors used the T-4/5s which are four and five speed stickshifts. They are also common to the CJ era jeeps, Before they went to Wranglers the later CJ transmissions were T-4/5s. If at all possible, avoid the
SR-4. It looks like the T-4/5 but has no ribs on the outside of the case and has been known in my area to suffer from case stretch behind four cylinders.
Good luck Keep us posted on thoughts.
