Engine/Transmission (1994 - 1998) Tach Jumping & 47RE TC unlocking

[Cumminsonly40]

'97 ram 2500 47re transmission is going in and out of lockup very erratically& tachometer is jumping throughout rpm range then going dead. transmission&tach mainly acting strange during first run of day when truck is cold then symtoms go away also 80,000 miles on original TPS. Any ideas?

 

[inarush76]

ideas

The problems could be related to crank sensor, tps, or possibly AC voltage leaking into system from alternator. When first starting truck cold, alternator output is high to recover batteries from starting truck and powering heater grids. Put a DMM across a battery at cold start up set on AC, start truck and look for voltage, . 1v or so shouldn't be a problem, but if you see 2 or 3 volts the alternator is bad. Hope this helps.

James

 

[shendren]

there are many threads on this. .



this seems to be a common problem... i experienced it at 50k mi. some say to spray the tps liberally with contact cleaner... ...



I changed out the solenoid / temp sensor/ and 2 tps'... ..... the only way to fix mine was to TAKE THE WIRES GOING TO THE TPS OUT OF THE HARNESS!! PULL THEM OUT ABOUT 2 FEET BACK FROM THE TPS AND PUT THEM IN THEIR OWN WIRE LOOM..... PROBLEM SOLVED!! NOISE!!