I have dealt with the TruckMart in the past, not my favorite because they are all part of the Harry's Auto Wrecking criminal enterprize here in Grande Prairie.
In my opinion I would forgo the 3500 torque convertor in preference for one with a much lower stall, I think you would find it much better over all for general use & fourwheeling. You could check with the guys @ Northern Transmission too.
--Ken