Dodge Repair: 98 dodge 3500 4x4

Question
I have a 1998 dodge 3500 4x4 with a dump box.this truck has a long history of problems.Recently had the transmission rebuilt,after that the motor won't run properly.the shop replaced the coil and the crank sensor this did not fix the problem.the coil on this truck has been replaced three times in the past 10000 miles,now they want to replace the fuel pump.the motor ran find before the transmission repair.Any ideas?

Answer
Hi Gary,
I wonder if you have any diagnostic fault codes. Use the ignition switch: "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see the mileage reading replace by any 4-digit numbers preceded by a P.  Let me know what you find. Tell me the engine size (L) and also what exactly is the motor doing improperly?
Roland