I own a 1990 Nissan Maxima with 250,000 miles on it. I have spent alot of money over the past years on it for repairs and maintenance which has let me maintain the original engine and transmission. I recently had a leak of fluids, so I had a repair shop replace a gasket between the engine and transmission, and all the seals in the transmission. Since then, my automatic transmission does not shift the same. As I accellerate, the RPM's climb higher than normal before shifting, or they do not change gears at all. This is an occassional but frequent occurance. Do I need my transmission rebuilt? Is it a transmission problem? Can it be fixed without rebuilding the transmission? Thanks for your assistance.