I got the thump sound again this morning, due the crap roads, it's hard to notice, but you do notice it.

It's like when you drive on pavement with a locker on. You turn and a locked wheel slips, you get that kind of thump and you sense something has just released itself from being under pressure.

It's happened several times, but I can remember it happening at the same turn on the drive to work, about 1 km after leaving home.

This morning it sounded like it came from the middle of the vehicle.

Could the gearbox or transfer case bind/wind up if the breathers are blocked???? The thump seems come from the middle.