how do i tell what gears my truck has in it? its a 1995 dodge ram 1500 4wd with the 5.9 v8

 

I believe there should be a label on the top of the glove box or on the underside of your hood that lists what your truck came with.

 

support rear of truck on jack stands. Put truck in neutral
make a mark on the driveshaft and note it's initial position.
make a chalk mark on the tire at the dead bottom.
spin tire one complete revolution and count how many times the drive shaft mark goes by. If it's 3 1/2 times, you have 3.55 gears, a little under 4 times is 3.92, a little over is 4.10, 4 1/2 times is 4.56.