2000 Dodge ram 2500 Shifting Problems

I have a dodge with 249000 miles and put a new engine and tranny in about 90k ago. the tranny has problems shifting from 2nd to 3rd. I have to let off the gas to get it to shift. or accelerate really slow. Any ideas? Please dont tell me I need another new tranny!! Also I think I have a small rear seal engine oil leak, anyone know how much that costs to fix?

Is this a diesel Ram??? With the transmission I would get a scan to see whether the computer is commanding the shift. These transmissions had problems with the governor pressure sensors so that needs to be addressed. How is the fluid level?? Remember, the fluid level needs to be checked with the truck on a level surface, trans HOT, and the gear selector in NEUTRAL.

transman

It is not a diesel. It has the 360 in it. Somebody told me it could bands that could need adjustment? Or possibly a speed sensor, the speedometer works fine though so I dont think it would be speed sensor. If it is the pressure sensor, what does that cost to have fixed. I will check fluid today and rule that out. Thanks alot for your help