I have a 2001 Ram 2500 long bed quad cab 4x4 turbo diesel with 150k miles on it. It had a bad solenoid and pressure sensor in the trans and both were replaced 2 months ago. Ran great. Now that it is blazing hot out here in NC, one in a while the trans downshifts and the engine gains 500 revs, usually at 45 mph where it usually shifts. When I turn the A/C off the problem goes away immediately. Then I get hot as almighty hellfire.

I read somewhere about an aluminum foil shield to prevent interference on the a/c power wire harness, but can't find the thread. Pretty sure there are no codes, but need to check again. Otherwise the truck runs great.

 

Check the wires coming off of the compressor for shorts, make sure the wire isnt grounding out somewhere on the block.

 

Hilbilli, I got a P0234 waste gate over boost code in the computer. Will check for floating ground at harness. Maybe the ground causes the overboost? Not sure, but do not want turbo to mess up iself or semthing else. Is there a general maintenance protocol for waste gate actuator? Like spray some lube on it?

 

Not sure on the maintenance procedure. But out of curiosity, do you know if your fan clutch is engaging?

 

The fan clutch is engaging and working fine. Also checked without it running, and the action on the fan seems like there is the little bit of resistance like it should be. Whatever, fan clutch is engaging.

The issue with overspeeding is now happening when the A/C is off. Beginning to think waste gate actuator, and need to trace vacuum line to do visual inspection. Also going to spray some penetrant on the lever that the actuator, uh, actuates.

Out of curiosity, could a CPS cause this and not kick a crankshaft position sensor code?

 

I sprayed the waste gate actuator with Deep Creep penetrant, especially where the actuator rod meets the arm. Seems to be better, but the feel of the vehicle is still a little different than it used to be. Can't say the problem has gone away, but it is much better.

Going to police the vacuum lines to make sure everything is OK with them. It's hard to hear vacuum leaks with all that diesel six banger going off.

Am I in danger here? Could turbo mess up? Should I go straight to the dealer and get another actutaor ASAP? Or continue with the DIY approach?