4X4 delay

[sau4u]

Hey all. 2008 F350. When I lock in my 4x4 by electronic only (not locking in hubs manually) the truck doesnt seem to actually lock into 4x4 until the truck begins moving. If I shift the truck out of 4x4 while on the move (5mph) or even less I get a clunk from the front. I have checked and swapped out my vaccuum pump with a spare I had in case that was the problem. any ideas

[GregsSD]

The autohubs work better if you are moving while shifting into 4wd, it lets the locking mechanisms slide easier.

And read through your owners manual, it states that the ESOF system is designed to engage 4x4 HIGH when the vehicle is moving.

[greasltn]

The hubs have to be aligned to lock automaticly. That's why you need to be moving.