skyler.surf

1998 tacoma 3.4 2wd with just under 141000. Just bought this truck about 3 months ago and I dont know that much about it yet. Only problem so far is it seems it doesn't want to shift some times. I come from driving 2 jeeps and I have read on the inter net that toyotas when running cold will use more rpms when accelerating than normal to get the engine up to the most efficient operating temperature. ( I'm assuming about 200 or 210 as jeep XJs run at) Makes sense. How ever today the engine was warm, I was doing around 45 mph and expecting the over drive shift to happen any time. But no the truck decided to down shift instead ( Engine is completely warmed up, AC/Heat off, Oil level normal, engine coolant normal, haven't gotten around to checking tranny fluid today). So i found my self doing 40 mph at around 4000 rpms and I could not get the truck to shift into a higher gear. Lucky I found some where to pull over quickly, (before burning the tranny up) nothing was smoking, no grinding noises or any out of the ordinary noises at all. I turned the truck off when I stopped, took the key completely out of ignition and cranked it up again around 5 min later. Upon returning to my commute (truck at normal operating temp) truck shifted normally and every thing was fine. This has also happened to me a few other times, only at 35 mph and the truck down shifting to do about 3 or 3500 rmps. I'm not punching the gas or any thing like that, I actually have a light gas pedal foot. Any ideas on whats happening here would be greatly appreciated. FYI I ride on 31 inch tires but there's no way the extra weight could be apart of this right?

Kiroshu

I would defiantly start with verifying proper Automatic Transmission Fluid Level.