Our ramps here are pretty long and some are very steep. Last winter it was 51 degrees and raining. I had just picked up the boat from getting a new intake gasket installed and wanted to try it out. As I was backing down the slippery ramp, the weight of the V20 pulled the truck down the ramp with the brakes locked up until the stern of the boat hit the water. Definitely a white knuckle experience!
BTW, my truck weights in at 5600lbs with me in it. With the 3.08 gearing it struggles to pull the boat out of the water. Fortunately I can just leave the front hubs unlocked and pull the boat out in 2wd low. It's got a locker in the rear which helps. I did use 4wd low on that wet ramp though just that one time.
 
I need to rig up a receiver hitch on my 6x6, then I'd have no problems at the ramp or feeling the weight of the trailer behind me...
