i HAVE 1996 RAM 2500,
The trans, (automatic ) shifts regular, until I am at a light, and I give it a lot of gas, then it shifts fine through 2nd gear, then takes alot to get to 3rd and forth. Down shifts irregular too, when going up a hill. But! if I shut it off, and start again, it's
fine. only when I drive aggresivly it takes a high RPM to get it to 3rd gear.
had the fluid changed, but still the same.

 

Welcome to DF! Moving this to the 2nd gen Ram section.

 

Standard problem. At large throttle openings, the governor pressure sensor sorta 'fails'... so the PCM doesn't know what to do with pressure. Replacing it might help.... or not.