It's been a while since I was here so an update is due: I bought an 1985 17' Galaxy Bowrider with a 140HP I/O back at Memorial Day. Its one trip into the sound revealed a rotten transom. Anyhow, I snatched that boat with a significant amount of water on board out of the sound with my 2007 2 WD 3 liter auto Ranger XLT as if nothing was back there. In fact, that was the only thing which went well that day. FWIW, it was a concrete ramp and I had to wet my back tires (hubs stayed dry) to get the boat to float off and back on the trailer (crappy ramp at low tide).
Since that time, I've been whipping the boat back into shape with a new transom and numerous improvements to the trailer. I have high hopes it'll keep the ocean out the next time I try it in the spring.
BTW, I found that the ScanGauge has the capability of reading transmission temperature, so that's one of my gauge displays. Riding down the road at 45 MPH in the winter may show 127°F-135°F with nothing behind the truck; pulling the boat in the summer heat maxes out at 165°F-170°F at 55 MPH. That is with a transmission cooler installed. Slower speeds give lower temps.