Shifting and down shifting issues

[Kevin]

After having a set of Toyo tires put on I experienced the engine working harder than before and the shifting while on the highway had trouble getting back to overdrive after passing or getting up an incline. Overdrive gear just not reengaging no matter if I slowed down or sped up the fourth gear just does not engage. I will sometimes have to shut the engine off and restart quickly to clear the problem. Another day I had a head wind and I spent most of that time for 39 miles or so fighting the wind, having to restart the engine 5 times. I slowed down even still the same problem against the head wind the transmision would shift down and when the wind subsided it would not shift back to overdrive. It seems to do it when it is hot and run for a while or against a head wind or an incline. I think the tires rubber is effected some how by the heat so I inflated the tires another 6 pounds over the ratings in the door jam. So now I am at 42 pounds which seemed to help. Along with that while driving along in 4th gear at any speed I can get this heaving where the transmission is attempting to switch down to third then back up back down and back up until I either step on it or foot off the gas. Seems to have had this problem but now it is more pronounced since having these new tires put on.

After the tire inflation to 42 pounds the problem was less frequent. I will probably try more air in the front tires to help improve roll and less resistance. The tire inflation rating is I believe 51 pounds. I will inflate the front tires to 47 pounds to match the rear tires. The rating inside the jam is up to 49 pounds in the rear and front I think is 37 pounds. I don't think that this will impact the ride to awefully bad and not harm the handling at all, these tires grab the road as I have had to make some quick moves to avoid hitting a deer and the truck stuck to the road like better than anything I have ever driven before.

Could this be a sign that the transmission sensor is flakey or some other issue which may require some rebuilding.

Current mileage is over 130,000mi, used on highway, through mountains and hilly terrain.

The transmission fluid has just been changed and the dealer said that they found no metal filings in the filter or fluid and if the problem continues to bring it back in which I just have not had the time to do.

The fluid has been changed at 60,000 and at 90,000 and now at 130,000. Doesn't seem to be a mechanical issue, all I can think is the tire inflation or a sensor.

I went up to the mountains the other day without a problem until I hit the head winds again and had to shut the engine off to clear the problem.

Whats your thoughts increase tire inflation or have the sensor replaced?

[vitalys]

I have the same issue right after dealer did second trany oil flush at 115,000mi started having problems shifting in/out 3rd gear and 4th and OD. Specially going up the hills with about 1,000lb weight in the van. What did you find out the issue with yours Kevin?