Auto Transmission Shifting Issue

[SCJax2018]

I have a 1996 LE with an automatic-overdrive transmission (not sure which one) and it has a crazy shifting issue.  If I take off easy, it will shift through fine, but get down on it and it is like it is stuck in high gear until you hit about 30 to 35 and it works like it should.

 

I replaced the fluid and screen in it, but the fluid wasn't really all that bad at all and there was very little crap on the screen or the magnet in the bottom of the pan.  The change did make a little bit of difference for the better, but just minimal.

 

Now this truck is supposedly sat for about three years before I bought it and it sat for nearly a year more before I got it running again and I've only put about ten miles on it since, so could this just be a sitting issue that will work itself out with a little time or is it something that needs to be addressed now?

 

[onespiritbrain]

Well it could be throttle position sensor issue. If it acts different depending on pedal position then maybe the sensor has a spot or section that isn’t right. I think they’re like $20 on Rockauto.

https://www.rockauto.com/en/catalog/infiniti,1999,qx4,3.3l+v6,1355778,fuel+&+air,throttle+position+sensor+(tps),5136

Sometimes the cheapest parts on Rockauto work just fine, then sometimes they are junk.. I would say go to the junkyard and grab one but I got a bad TPS for mine at the junkyard. It’s an important part for it to not be working right.

It could also be slow movements inside the transmission’s valve body. There was a person on this forum with a transmission that wouldn’t shift past 2nd until it was warmed up. He pulled a valve body from a RE4R01A that was in a 2003 Xterra at the junkyard and stuck it in his Pathfinder and it completely cured the problem.

Id start with the TPS first, then if that doesn’t work then you might consider the junkyard valve body.