Got a 2003 Silverado 1500 Z71 with 93300 miles. Going from 1st gear to 2nd gear there seems to be a hesitation/rough shift. It doesnt always happen. Really depends on how I accelerate etc. Ive done alot of reading and it seems to be a common problem. I plan of getting my transmission fluid changed (not flushed) as well as filter. I would like to add an additive to try to smooth things out. Does anyone know what I should do or try? I was looking at the SeaFoam tranny additive. I also heard spark plugs can smoothen things out. Is that true? I picked up a set of ACDelco iridium spark plugs as it wont hurt to change them anyways. Should I change wires too? If so what kind? Also what kind of tranny fluid and filter should I use?
Sorry for all the questions and thanks in advance!