I have a 2001 QX4 with 170k miles. When the weather gets cold & I get in it for the 1st time, it will do a high rev (slip?) when shifting through the gears. Once the truck is warmed up the problem goes away. I've looked online & saw a few people saying that it's the transmisson ECU that causes this. Does anyone else have this problem?

I had the same problem but changing the transmission fluid seemed to solve it. My fluid was clean to but apparently was not able to do its job.

I did a fluid change, but it didn't help. :(

I know this post is old but didn't see a resolution. Was it the ECU. I'm having similar issue only it doesn't go away when warm. Mine is 1999 Infiniti QX4 and it runs fine through gears 1 & 2 but when it shifts to 3rd (drive) it disengages or slips. I don't feel any vibration as I would expect from a slipping transmission. It feel more like going to neutral. The tach goes way up but no drive.

Never found a solution & have been driving it daily ever since. It hasn't don't it in a while, but the transmission occasionally has some shift prblems from time to time, depending on how i drive. 217,000 & the engine purrs like the day I bought her.