snow

On the 2001 pathfinder is there any preventative maintenance that can be done to prevent the coolant from getting onto the idle air control valve?

Hi folks, just recently my transmission has been acting up. It was 23 below this morning and after a minute of driving I was on the highway, and the pathy wouldn't shift into 4th gear. I was in 3rd doing 90km/hr at 3500RPM, revving it to 4500RPM still wouldn't go into overdrive. After 5 minutes of driving in 3rd gear doing 90km/hr at 3500RPM the RPMS dropped and it was in overdrive. This is the first time this has happened to me, just wondering if anyone has any advice.