Hello all. I am a newbie to the forum and hope that someone could help me with an issue. It is regarding my dad's 01 Ram 1500 5.9 automatic. Its got around 60k on it and started acting up recently.

When cruising in high gear at appox 40 mph or so when he gives it some accelerator the truck acts bogged down almost like its a stick shift going to slow in high gear and needs to be downshifted. If he punches it and it downshifts or slows down enough to downshift on its own its fine. It only acts up under these circumstances and otherwise runs perfectly.

He has changed plugs, wires and distributor cap. Had the transmission checked and its fine.

Its driving him nuts-any help you can offer I would greatly appreciate.

Thank you very much.

 

Welcome to the forums.

How long has your dad had the truck?

That sounds normal, O/D is a dog in these trucks, designed for MPGs. Take O/D off, and you won't have that issue. (Button on end of shift lever.)

Many here (myself included) don't engage O/D unless we're going over 45 or so. Probably help your tranny live longer too.

 

+1 turn OD off.

if its still a slug, replace the throttle position sensor (TPS), drivers side of throttle boy, about $40-45 at any parts store. it might help. if it doesn't help, keep the old one as a spare part. TPS is one of those things that fail and its nice to have a known good part to swap.

 

Thanks for the info. I have told him about the TPS. After reading up on TPS I see that partially controls when the transmission shifts from 4-3 and 3-4. This is when this problem presents itself so maybe that is it.

Again, the best way to describe it is for those of you who have driven a stick shift is when you are going too slow in high gear and need to down shift. The whole truck sort of vibrates and when downshifted runs perfectly again. Its definately not supposed to be doing what it is.

 

A vibration? Why didn't you say that in the first place! You're right, it shouldn't vibrate.

Definitely +1 for checking the TPS.

 

Yeah at cruising speeds you will get that. Mine does it on th highway. its the 4.10 if you got that pkg. Should be bad.

 

The truck does'nt do it when not in overdrive. According to him it only acts up like that when in OD. Is that still a possible bad TSP? Thanks again very much.

 

TPS (good or bad) won't directly affect shifting or vibration.
all a good one will do is accurately tell the computer where your foot is in the gas pedal, without having dead spots.

and honestly, an automatic, in overdrive, with torque converter locked up, at 40 mph, is exactly the same thing a stick shift going too slow in high gear. the engine doesn't have enough torque to pull it and it does produce a shaking feeling.

depending on tire size, OD and is not practical until you get a little more speed. up around 50 or so.

 

Thanks for all the help. This is a tough one. The truck is definately not supposed to do what its doing. He has had the truck about year and it just started.