99 2500 quad cab. trans shifting in and out of overdrive driving at 42-45 mph driving on a flat surface. truck has been doing this since bought two years ago. had to change input speed sensor the the trans oil has been changed. no help. i purchased the actual shop manual for this vehicle trying to solve problem. i have brought truck to CERTIFIED DODGE FIVE STAR SERVICE CENTER as prompted when i emailed dodge for information. Dodge service center reflashed the shift computer. the mechanic then said he does not know how to fix shift problem. He said that dodge is aware of the problem but is not doing anything about it and they will never admit problem. Taking it upon my self with the service manual, i got an idea that the throttle pos sens may be bad. ckd out good. I also have cleaned the battery post via the dodge serviceman and it helps but doen not fix. i have also determined that the tps works on millievolts, and voltage is critical. My truck has a post-heat mode for the intake air. when below 66 degrees, it kicks on and off dropping the voltage in my system causing the trans to shift. But it also does it in summer.. so also not the fix. I am about to solve this trans problem by buying a powerstroke, unless i can get some help. gas milage is down because of shifting prob. sorry to bore, just want help

 

I have an 01 and my trans does the same thing, so the only way i found that works to solve the problem is to drive around with the overdrive off and only turn the overdrive on when i know my speed will be 50 or above. It does have a slight effect on mileage but i rather go that route rather then deal with the annoying shifting in and out of overdrive.

 

Wifes 98 did the same thing their is a electronic filter that i think BD makes that will filter out the system and allow it to shift right we spent about 100 bucks and didnt have a problem so far

 

My '01 does the same thing. I just usually drive a bit faster if I can.

The other way I control it is to lock my torque converter clutch with the Torque Lock. The tranny doesn't downshift with the lock up engaged. I really like the Torque Lock by the way. It allows an added level of control to the tranny and it is very helpful in the mountains.

 

It most likely is electrical noise in the alt. A noise filter is a good idea. DTT has them.Diesel transmissions .

 

I had the same problem with my truck. I put a Happi box on it that did little to help. I talked with the folks at DTT and they had me pull and clean all of the wires to both batteries, on both ends. That completely fixed my problem. They do have a filter for $37 that would have been the second step.

 

Ok, whats a Torque Lock? A way to control when the converter locks up? Is it a "boght" item or can it be cobbled together? Thx.