is this a tranny problem? RPM goes up when cold

[Guest hugo0612]

I have a 94 pathf. auto tranny 4WD 110K, I think when tranny is cold the RPM goes up and down and tranny seems to work harder when this happen.

only when it is cold, speed 55-60 miles the RPM will be 2300 and it jumps to 2600 for a few seconds and then comes down to 2300. is this a tranny problem? please help, thanks. :help:

[Reido]

Sounds pretty harmless to me. Probably just droping into a lower gear like 3rd (these transmissions are 4 speeds right?) The reason you notice it when cold could be related to the engine control running the engine at lower loads when cold or viscosity of the transmission fluid.

[denisb]

The tranny going from 2300 rpm to 2600 rpm at highway speed sounds like your tranny is just coming in and out of lock up. This would happen mostly when you're coming off the accelerator, but it might happen going up hill or if your rig starts to labour too. If it does it ecsseivly you might have a problem with your lock up solnoid, but it's normal to do this.

[88pathoffroad]

If you haven't installed an external tranny cooler and bypassed the stock one yet, do it. You may save your tranny's life.

[Guest hugo0612]

The car was not doing this before, what do you recommend?

to install a new tranny selenoid or a external tranny cooler? are this easy to do or expensive?

Thanks

[93blkpathr]

What's the fluid look/smell like? Change the fluid and install a cooler and you should be ok.

 

Mine will do this on occasion at torque converter lock-up after driving for a long time and new fluid seems to help out if it starts happening a lot.