until 96 they had the gear in the tailhousing like a 904 - 727 but in 96 they got an electronic speed sensor in the tail housing for the govenor and a speed sensor in/on the diff that reads the axle speed and gives you your MPH so if your truck is 96 or newer you can change gears and your computer will never be the wiser

I wish you were closer with those 3.55 gears I would swap them for my 3.92s

I am not causing global warming, I am just trying to hold off a impending Ice Age!