I have a 2000 Dodge Ram Van 3500, ext cargo, ext height conversion van. It is powered by a 5.9 Magnum V8 with A518\46RE Auto trans and 4:11 rear. It has just turned over 180k miles. When I first bought this beast, I had Mr. Trans exchange trans fluid and filter, engine oil and filter, P.S.fluid, rear diff fluid, and clean and adjust rear brakes. Also had a new exhaust with high flow cat and flowmaster muffler. Personally, I have done: front brake pads, rotors turned, new bearings, plugs,cap,rotor, TB mod with JY part (still testing it out), 4 shocks, belt and pulleys, K & N filter, pcv valce, crankcase breather. This van runs and sounds great, better than that, actually, AMAZING....just one small intermittent issue....
On the way home(weeks ago), the engine spontaneously revved super high and the transmission "fell outta gear" ...when i pushed on the gas pedal, no increase in momentum, but increase heard in rpm. Pulled over and checked fluid, it was between the marks. (I have replaced fluid and filter 2x since ownership) I was able to limp home, during the last few miles the van drove problem free normally. This marked the beginning of an intermittent trans malfunction that was later explained to me as voltage signal lost to the gov. press. sol..
I had it towed to double ay, em, see ,ohh and they told me it was an internal trans problem. $2,150.00I later I have a rebuilt trans (and fancy new cooler) with the same intermittent problem. Took it back for more solenoids, clips,and harnesses, even got a new O2 sensor (downstream). Still acts up randomly. They took it to dealership to confirm their suspicion of the PCM, but dealer stated in B&W there was an internal transmission problem...possibly "in the drum" . Trans guys jumped a wire close to pcm connector harness to trans harness, no change. I have had it back there 5 times, the fifth was an entire week long.
I replaced the TPS with a another I bought with the junk yard throttle body. no change...I replaced the PCM harness with one from identical vehicle....no change.
What am/are I/we missing?
I don't know what else to do! Throwing parts is not practical when considering the price of a new PCM & Programming. (yes i tried the online computer exchange and the experience was pathetic and the REMAN part BOGUS)
I know there are other engine sensors in the same 5v PCM circuit as the gov press sol, but REPLACE THEM ALL?!?! Are there better ways to test each individual sensor?
Clearly I don't own a DRB scan tool, but how can I know for certain the PCM is at fault? (Mopar reman dated 2006)
Should I buy a new TPS? Or have a shop sweep both TPS and Alternator with an oscilloscope?
I am proficient with my Fluke true RMS multimeter, and I do have the service manuals and haynes manual.
Any suggestions are greatly appreciated!