So it was wet and slick on the way home so I decided to engage the 4X4 to give it a little work out, myself and the previous owner hardly use / used it so I thought it would be a good time to get the fluids moving in the front diff and t-case. Drove two or three miles on a strait two lane road and and about 40 to 50 MPH, and my turn was coming up so as I coasted down to approach the turn I disengaged the 4WD. I was doing about 15 MPH when I flipped the switch while coasting, and about 5 seconds later at about 10 MPH the was this loud clunk almost grinding noise and felt it in the floor board. What in the world could that have been? I have used it before and I did not have any issues, later that night I tested out 4 high and 4 low and there was no issues.

2008 Crew cab Lariat 4X4 6.8L

 

so long as its working now i wouldnt worry..prolly has some torque buildup in the driveline that releived

even thou 4WD systems are shift on the fly, i never use em that way..

get into or out of 4WD BEFORE u think u might need to not after.

if ur sitting still while u shift into/out i bet ur 4WD will never make that clunk again.

 

I guess my question would then be, has anybody else had this happen, and can it be considered somewhat normal? Thanks!

 

I was thinking about the whole thing and now I know why it might have done that, I had the tow haul mode engaged, and even though I was coasting to a stop it was holding the gear, and therefore the drivetrain was loaded in the opposite direction.