The t-5 could be made to work, but would not recommend it. The first gear ratio is too high, and the tranny it self is not designed for huge amounts of torque the larger tires and lower gears will give it. The real question is the ZF vs. the NV3550. I run the ZF, it bolts right to the small block fords(ie 302 or 351w) and to a NP205 transfer case. It has a granny low with a .76 overdrive 5th gear. It comes in F250 through 450 from 88' to 96'. There are two styles the S42 (pre-93')and the S47(post 93'). Comes in gas and deisel, you will need the gas 4wd model. The S47 is the cream of the crop, bigger synchro's, but the 42 like mine is great also. The NV3550 is a little lighter duty, but shifts smoother with not as low of a first gear. Street driving is better with this set up. Cost wise the extra money spent on the ZF will be recouped by not having to buy all the extra adapters to make it work. Hope this helps......