My auto trans starts by jumping not completely out of over drive, but it increases RPM by 150-200 when it occurs. Eventually it gets bad enough where it completely jumps out of overdrive. It is presently at a dealer, and they can find nothing (no codes). Seems to be worse in colder temps (20-25 deg F) outside. Any ideas??

 

What?

Can you describe what's happening more clearly?

 

When driving down the highway 55-70 mph, truck RPM's will jump 150-200 RPM higher (seems to be downshifting, but not completely out of overdrive if that makes sense). Truck would fail on upgrades, downgrades, flat road, did not make a difference.

Over time, (approx 15 miles of driving) this gets more frequent, until truck completely downshifts out of over drive. But if you let off the accelerator, it will go back in O/D but will fail again.

Dealer has replaced throttle position sensor, but truck continues to act up. They have just recently put in the lift pump upgrade (pump in tank as apposed to mounted on block) and they say that this has cured the problem. Low fuel press was the only code they were getting.

They have to continued to drive it the past few days, and can not get the problem to return.

My question is, could this have been a fuel problem? I never noticed a loss of power. Just seemed like a trans issue the whole time.

Hope this is specific enough. Thanks for reading

 

Sounds like your torque convertor is unlocking, then the trans is downshifting.

Generally this will happen if there's increased load. Was it happening while towing? On hills? In extreme wind conditions?

 

No not at all. Just driving empty truck down the highway. It would happen equally on hills, flat ground, and downgrades.

 

We could help alittle more if we knew what year your truck is.
Fill out the profile, please.
Next time it does it, turn off overdrive, to see if it is od instead of the converter clutch.
BTW if it shows no codes, some dealers are lost!!!!!!!! Poorly trained.

 

Sorry, 2003 2500 4x4.

 

Mine did the same thing when it was new. Turned out to be some sensor in the trans.

Nick