October 18, 2003
Im assuming your tranny is automatic.
Heres how to tell what you have. Either 700-R4, TH350, and TH400. More than likely the 700 or TH350 but it might have soemthing different swapped in. First off, check if it has overdrive. (not by looking on the steering column, feel the gears when you shift and see how many it has) If you have over drive it should go like this- P R N (D) D 2 1
And if it has overdrive, you have a 700-R4.
If it does not have overdrive- P R N D 2 1 its either a TH350 or TH400. To determine what one of them it is, crawl under the truck and look at the tranny pan. If the pan is square, with one slanted corner its a TH350. If the pan is "texas" shaped with a slanted corner and another dohickey on it, its a TH400. This is probably the easiest way to tell what tranny you got without running numbers. If you have the 700-R4, im my experience has been nothing but useless junk. But i know a few people running these trannys with no problems. The TH350 is a good tranny found in earlier model 1/2 ton trucks and the TH400 is the toughest. It was found in 1 ton trucks and i`v seen them in 3/4 tons as well.