Hello,

I have a 1996 Montero SR with 183k miles and the transmission shifts hard from first to second, at higher-than-usual RPM of 3.5-4K, but only when the engine is cold (even though temperatures outside are in the 80s), and always only one time at the beginning of the drive.

Once it shifts from 1st to 2nd the first time, it shifts fine from after that. I have recently replaced the fluid (not flushed) with Diamond fluid, and that did not change the issue. The truck is so smooth besides this issue.

Could it be a computer issue?

 

It doesnt sound like an ECU problem to me. Id start yur rig up in the morning and check th COLD level it sounds like your low on fluid. If you havent done that already thats where id start.

 

Looks like the fluid is at a good level both when cold and when warm! I really have no other leads, as there are no warning lights and the issues completely resolves itself after the first shift. Perhaps the memory of the shift computer is corrupted?

 

Throttle Position Sensor most likely needs to be replaced...Had the exact same issue for about a year and finally replaced TPS..shifts smoother and seems to be getting better gas mileage

 

reset computers anyway. Nothing to be lost.