This sort of a general automatic tranny hint, but works especially well with the Isuzu 4X4 trucks:

When parking the truck don't move the gear selector directly to park before shutting down. Move the gear selector to neutral "N" for a brief moment, then on to park "P". In most cases you'll actually feel the torque converter and driveline unload when in neutral. This prevents the driveline from sitting under tension until you next use the vehicle, which is what typically causes the clunk when getting started.

When I got my first Trooper many years ago I would get startled when just sitting a light there would be a clunk noise and slight shift of the truck. I eventually learned this was the driveline unloading and perfectly normal. Ever since it's just been a part or being an Isuzu enthusiast. Except for the manual trannys, of course.