I traded in my 2004 1500 qc 4X4 hemi with the 5 speed automatic and bought a 2005 2500 qc 4X4 hemi with the 5 speed automatic. The 2500 seems to shift much crisper or firmer. I had a flashpaq 3815 in the 1500, and that helped the shifts alot. Now I kept the flashpaq and installed it in the 2500 and used the same settings. The 2500 again shifts MUCH firmer, especially if I keep the pedal down and let the rpm's get up over 4000 before it shifts. And it is head-snapping at full throttle shifts. Is the 2500 transmission different from the 1500 transmission? Or is it the 2004 to 2005 model year that makes the difference?

 

It must be in the programming since they are both the 545-RFE trannies.

 

Thanks. I thought they were the same. The 2500 must be programmed a little different from the factory. I have the flashpaq's shift rpms turned up pretty high, and I connected 12V to the PTO input wire, and I love the way it shifts. I think that is why the 2500 guys see 1/4 mile and 1/8 mile times not too far behind the 1500 guys with the same major options (qc or 4X4). The 2500's seem to not lag on take off as bad and seem to shift much quicker. It is amazing how a few tenths can be lost in a slightly sluggish shifting automatic.

 

That makes me feel quite confident about these auto boxes.
The 2500 is so much more, a big brother to my 1500, I feel somewhat easier to think that the same auto box, powers both.
Al.