If the truck is cold, it wont do it right away, as soon as its up to temp it starts...
As long as you acc. everything is fine, the problem starts when u let off the gas, it makes a sounds like the t-case is trying to engage. when u put positive force on the drive shaft it stars to go away, then comes back at a coast.
I've been told its the drive shaft which I'm almost 100% its not, i was thinking of buying a new t-case, but then talked to someone else and he talked me out of it and to save my money, he said its probably something simple like needing a cv from a Tacoma but i told him it never did it before so something has gone bad.
any input would be appreciated