I have a 2k GLE with auto tranny (of course) and a VB mod with a B&M tranny cooler. I have approximately 67,000 miles on it, mostly highway. Just changed the AT fluid about 5,000 miles ago, and am using Mobil 1 synthetic.

I was on my way home from Las Vegas yesterday. The outside temperature was about 100 to 105. I was running the car pretty hard up a long hill, going about 90 to 100 pretty much all in 3rd gear with no overdrive. Once I got over the hill and was cruising the tranny would not engage overdrive. I tried slowing down, shifting into neutral then into drive, and shifting from second to drive but to no avail. I also saw that when the tranny did want to engage overdrive it was not catching 4th gear; it wanted to shift to it, but basically felt like it was in neutral and the RPM's went down to about idle speed. Even when giving it gas it would just jump the RPM's up and was slipping, when the RPM's hit about 3500 it would catch 3rd gear, but never 4th (overdrive). I was perplexed...I had this happen once before, but not to this extent. I remember shutting down the car and starting back up and the problem went away the first time I had it. However, I tried that this time and it didn't help. I finally stopped at a gas station and doused the tranny with water to cool it down because I figured it was a heating problem. I was right, it worked and the tranny shifted like it should from then on.

I was just curious if anyone else had this problem before? At one point my head was running with what I needed to change back to stock on the car to get it into the dealer to keep it under warranty repair (I have 100K warranty). BLAH...just a lot of heartache, and weird altogether.

Any thoughts?