I have a 98.5 dodge 4 wheel drive with a 24 valve cummins and automatic transmission w/ overdrive. Just the other daythe trannystarted acting up on me. Once I getbetween 50-55 mphit will shift up a gear and immediately back down a gear. It will do this repeatedly until I'm at about 60 mph.I read on here that some guy had this problem and replaced his air filter and the problem went away and a few people said that it's most likely corroded or bad connections at the battery terminals, so I put in a new air filter and cleaned all the terminals. Still shifts itself to death. Is there any sensor that would go out or something? It shifts great and there's no slipping or anything just doesn't know what gear to be in between 50 and 55 mph. Any help would be appreciated, thanks.

 

Bad connections at the batterys. Clean them up and see if that fixes the problem.

 

I tried that and there wasn't any change. Somebody here said something about the tps on the 12 valve models, is there anything similar to check on the 24 valve trucks? Or is there anything inside the tranny that would cause this?

 

I still think it's a badd electrical connection. I have the same truck, and I had the same problem. Not only do you want to THROUGHLY clean all of the connections at the battery terminals including the cables, but you also want to throughly clean the ground wore to the block comming from I think it's the battery on the passenger side. Make sure the block is cleaned in that area as well as the cable.

To answer your question about a sensor, YES, there is a sensor, however I think it would through a code if it went bad. I just repaced one of those as well.

 

get the tranny serviced and ask about the gov pressure sensor. I had a couple of them go bad and it causes some wierdness in the tranny shifting. your sounds like it's dropping out of OD which is not good... get it looked at asap

 

I just had autozone scan the computer and it came up with code PO720, Definition: low output speed sensor speed above 15 mph. Explanation: Vehicle speed above 15 mph while transmission output shaft below 60 rpm. Probable causes: 1.Failed output shaft speed sensor 2.Electrical problem. The weird thing is that the check engine light didn't come on but they still pulled a code, doesn't the light come on when there's a code?

 

I just swapped out the speed sensor because it was only $20.00 and thats what the code called for but it did nothing. Now it's time to double check all the wiring and connections. As far as it dropping out of overdrive, it has this problem even when I have overdrive switched off. It seems to be kicking down a gear right after it shifts into a higher gear at steady cruising speeds only. If I step on it theres no problems it just goes, but once the rpms mellow out to cruising speeds thats when it shifts back and forth. Thanks for the help guys.

 

there used to be a flash for the computer on the gas trucks that would help stop this problem. im not sure it is the same for the ctds or not. tomarrow when i go into work i will ask my uncle who has built tons of dodge truck trannys and will be doing mine soon. hewould betterknow whats wrong with it than i would.

 

i have a o8 that does this between 20/ 30 they say it just needs a upgrade ......ever hear of that?

 

No never heard of that, sounds like B.S. to me.