Ok this could be a long one.

My truck is a 1994 ram 2500 4wd 360 5.9l auto trans. The problem starts with the transmision, At any speed and at any givin time my trans "lets go", (almost like i shift it into neutral) sometimes it kicks back in on its own, other times i have to shut the truck off and fire it back up then im good to go for another couple kliks. some days i could drive for hours and not have a problem with it... sometimes it does it just after start up. Now i can ussually tell when its about to let go because it makes a strange sound in the bell housing, like the torque converter. A reall loud wining almost grinding noise. When the trans is working there is no slippage at all, wich leads me to think this is electrical. Also when the truck is idleing it will start to suck air really hard and almost kill the engine..(like the IAC valve is closing), I also have one taillight out that i cannot seem to fix... Not to mention i get about 300km to a tank of feul... if i drive nice... Im starting to think all these problems are steming from the same cause, Something electrical. I have replaced...
-spark plugs
-TPS
-IAC valve
-O2 sensor
Ive taken all the grounds off cleaned the mating surfaces of them and re-atatched them, I have reset the PCM many many times.
I checked the codes and all i get is

-12----- Batt has been disconnected in last 50 key cycles (SO?) lol
-21----- No fluctuation in voltage from O2 sens to PCM (probly same problem has been replaced twice)
-55----- End of code cycle (Oh! Good!) lol

Im willing to try anything to keep the ol girl alive! My 09 is commin soon but that doesnt mean i can let faithfull just sit an look pretty right?!? lol
Thanks for any imput guys!

 

Just take it to a transmission shop. They are the only ones that can diagnose the computer and let you know what's up.

 

Hmmmmm... I was hoping someone wasnt going to say that, But i guess thats what ill have to do, ok thanks!

 

You could try finding a service manual and going through the diagnostic section. That's the same thing that a mechanic at a dealership would do. We have a link to one on here, but it is for a 2001.