Transmission problems! Help!

[mudcharger]

I have a 1999 Dodge 1500 4x4 5.2L. The truck seems like it keeps going in and out of neutral, or it might even be shifting in and out of overdrive fast. Sometimes its a nig jump in rpms (1000) and the whole truck jults alot. Sometimes its small (200-300rpm). It seems to only do it when it is warm outside, and it doesnt do it the whole trip it started doing it this fall and never did it the whole winter until recently when it started warming back up outside. I did take it to a shop, they said it only popped one code up wich was p0420 and they changed o2 sensor and it cleared it. They said the shifting wasnt consistant enough to get a proper diagnosis. The truck has approx 138,000 miles. I appreciate any ideas! I just need it fixed before it explodes!!

 

[leadrofthepak]

This one could be tough to nail down. There are so many things that can create an inconsistent stuttering. Intake Plenum gasket failure, TPS fatigue, governor pressure solenoid clogging...
Check your transmission fluid for correct level, smell, and consistency (truck must be level, running, and in neutral)
See if you can nail down exactly how to make it stutter, make note of all driving conditions when the problem occurs (driving speed, rpms, light throttle or normal throttle or wide-open-throttle, stuff like that).

 

[mudcharger]

Hello, I have replaced the motor about 9000 miles ago (give or take) it had a bad plenum gasket so i replaced it with one from huges engines (1/4" aluminum plate). I have already checked my fluid and it checks out in all aspects, as it has gotten warmer out it has changed its mph when it does it, it usually does it under normal throttle (2000 or so rpms)

 

[dodge dude94]

Have you tried flooring it to see what it does? Your description sounds almost like a misadjusted throttle valve cable at the throttle body on the engine. That cable controls the line pressure of the shifts.

 

[mudcharger]

Yes, sometimes if it is messing up extremely bad I will floor it to get up to around 80 mph, it doesnt seem to do it then when im keeping it that fast (2000rpms) but it will still do it if im going slower. I took throttle body off the other day to clean it and clean sensors, took all the cables off and made sure everything was good. Still does it. ALSO keep getting a p0420 code, changed o2 sensor (was bent) and it cleared it, just took it for a drive a bit ago and came back on... possibly a bad cat? Would it do this? And i have changed output speed sensor on trans too btw. Thanks for all or your help and ideas!

 

[leadrofthepak]

I am pretty sure a bad cat will foul your O2 sensors.

 

[Mega-Hemi]

Do the rpm's seem to jump around while at a steady cruising speed? Does it seem the TC clutch is unlocking when you hit a bump in the road?

 

[mudcharger]

But will a bad cat cause these issues? And hitting bumps in the road do not effect the problem, It doesn't always do it when im driving its kind of hit and miss, like i said it seems to do it only when its warm or hot, only seems to do it 40° and warmer outside (until recently above 34°) one time it did it i stopped in a rest stop and put the trans in neutral to cool down, got back on the highway and it only did it once the rest of my trip.