RPM Drop after warmup, but no shift

[phil_01_s]

I am wondering if the following is common or if it is cause for concern:

On cold mornings it takes me about 3min of 35mph driving to get to the interstate, which I hop on accelerate up to 65 or 70mph. I notice that my RPM's in 4th gear are about 200-300rpm higher than usual. After about 2-3min at 65-70mph the RPM's drop to normal (65 is a tad under 2500rpms usually, but on the cold mornings before it drops it's at a constant 2700). It's not shifting from 3rd gear to 4th gear as the initial RPMS would be higher and there would be a noticeable downshift, there is no noticeable downshift with the RPM drop.

Anyone care to explain what is going on here if it is normal and no cause for concern? I've only driven manual tranny's before this. Do I need to have something checked out?

Thanks,
phil

[2eyefishclaw]

possible torque convertor clutch problem
how is the tranny fluid how often do you flush the beast out

[phil_01_s]

It's a 2001 Trooper S, auto tranny. I bought it used about 2yrs ago. Receipts show it had a tranny flush Sept 2004 at 47k miles, so It's been 2 years and 19k miles since.

I don't know much about transmissions but it just doesn't make since that I my RPMS can drop, I stay in the same gear, and the speed doesn't change.

[atfdmike]

Hi, I have a 94 trupr that behaves the same way when cold. I think the torque converter does not lock up unless the powertrain reaches a certain temp. I too would be interested if others have similar behavior in their truprs.

[phil_01_s]

I took it by a transmission shop and explained what was happening, then the guy/mechanic tok it out for a test ride w/ me along. Nothing is wrong with it, it's normal for the torque convertor to not fully lock until the engine/powertrain is up to the right temp. Just wanted to provide an update in case anyone else has the same problem. No CEL's.

[Ramblin Fever]

Sounds normal to me on cold mornings, mine behaves same way, has for 9yrs.