my zx needs to be at running temp before trans will shift up

[dJohnn]

On the start of the day, when going on the freeway, the transmission will not shift up to the highest gear until the car has reached running temperature. I am going 50 mph and the tach is reading 2800+ rpm, once running temp is reached I can feel the up shift and everything is fine.Any clue to the cause and remedy of this would be appreciated.

Thank you,

dJ

[Q451990]

My mom had a 1998 Maxima that would do the same thing. Even worse, it would hunt in and out of overdrive for a while - very annoying.

My solution was to replace the thermostat... turns out the car wasn't warming up completely and it was taking a long time for the system to warm up to near normal with a partially stuck-open thermostat.

The car is designed to lock out overdrive until normal operating temperature to keep the engine from lugging and to warm it up faster. It can tell either by looking at the engine temp. with the ECU, or some Nissan transmissions have an internal temperature sensor. If you get the engine temperature hot enough as quickly as possible, you should be fine though.

Good luck!

Heath

[AZ-ZBum]

On the start of the day, when going on the freeway, the transmission will not shift up to the highest gear until the car has reached running temperature. I am going 50 mph and the tach is reading 2800+ rpm, once running temp is reached I can feel the up shift and everything is fine.Any clue to the cause and remedy of this would be appreciated.

Thank you,

dJ

That's normal. The transmission won't shift into OD until the car is warmed up to prevent damage to the transmission.