A transmission temp gauge can head off a lot of this. Rocky Mtn Ray went to a lot of trouble and expense to have a conventional gauge installed in his Tundra. This required finding a mechanic who would drop the transmission pan, then drill/tap/braze a sensor into the pan, and install a gauge in front of the driver. He reported that it works really well.
An easier (and I think cheaper) approach is the Interceptor gauge. It simply plugs into your car's OBD (on-board diagnostics) connector - every vehicle sold in the US since the early 90's has one. It turns out that the transmission reports its own temperature to the engine computer, and the Interceptor simply intercepts (hence the name) that computer message and displays the result.
I bought one, and it's great. I think Keith Wire bought one as well. It doesn't cool your transmission, but it lets you know when the temperature is rising so you can either downshift, or ease off the throttle. At $200, it is not cheap, but it's cheaper than the sensor-in-the-transmission approach - and certainly cheaper than a transmission rebuild.
This gauge was brought to the board's attention by dcairns (no longer a member). See the discussion beginning at post #9 in
http://www.trailmanorowners.com/foru...ead.php?t=2900
The manufacturer's web site is
http://www.aeroforcetech.com/Interce...eral_info.html
Bill