Thanks for the info on the transmissions Jerry. I can always count on you to answer my questions about these Isuzu diesels. I think I will consider to use the 4-speed trans and 4.11 axles in my Trooper. I have located a 1986 Trooper diesel 5-speed trans that I wanted to buy to have that extra gear. But I had a gut feeling that the 4WD 5-speed was similar to the 2WD 5-speed in durability. I also wanted to keep the 4.56 front and rear axles for the extra towing power, as the axles will do much of the work anyways. The 4.56 axle is a tree stump puller! The lowest axle ratio I have ever known about in a passenger vehicle is probably 4.88. So am I really better off with the 4-speed/4.11 ratios than the 5-speed/4.56 ratios, along with the upgrade of 33x9.50x15" tires?? I only plan to use my Trooper in winter weather and on roads where the speed limit is 45-50 mph. It is a vehicle I don't tend to run on the highway, but more so in town. Jerry, I also had another question to ask you. For the 84-91 1st GEN Trooper what was the first year you could get limited slip differential in the rear? Thanks.