Help! I have a 98 12valve automatic and the transmission is starting to slip a little and will shudder around 65-70 when I get on it. The only mods I have is TST 230 plate, 4" JRE exhaust, and guages. I have 50,000 on it and my first thought is to change the fluid & filter. I was thinking of a valve body or T. C, but I am planning on getting a new 2001 in the spring (yes a Cummins!!, but really want a crew cab) so I don't want to put alot of money into the transmission. Finally my questions. What type of fluid is being used the most? My local dealer said I can't run the new +4 mopar synthetic and have to run the +3 being mine is a 98. Also, my local dealer does not have a flushing machine so he only drops the pan and changes the filter and whatever is in the pan. Should a guy have it flushed or is just dropping the pan good enough?