Does the '07 F150 have some type of auto locking front hubs, or is it always engaged and the transfer case just send power to the front when you engage it? The reason why I'm asking is, the other day I was on a job site at work that was rather muddy. I put it in 4wd LOW range because i was backing up to connect to a generator that I was going to move. Backing was fine and I didn't notice anything different. After hooking it up to the generator, I put it in D with OD off and went to pull it out of the muddy soup pit it was sitting in. I went however far it is until it shifts into 2nd gear and I heard a really LOUD (!!) CLUNK from what sounded like the front driver side wheel. I continued pulling the generator (and my truck) out of the pit to solid ground. Once I got to the solid ground I unhitched the generator and drove off to the asfault (still in 4x4 LOW range) about 300 yards through the mud. Once I got to the asfault, (still in 4x4 LOW) I turned left on the asfault to go back to the main paved parking lot. The 4x4 system started to bind when I got to the asfault turning left, do I know I had power to the front axle the whole time. I guess my question is, what was that REALLY loud CLUNK that I got from the front end???? Is it something that I have to worrie about (the truck is still under warranty, 21k miles and it's an '07). Is it that the front end didn't quite lock in yet, and it did lock in under power? Or is it that there might be a failure in the 4x4 system???

 

The 04 up F150 has IWE's, integrated wheel ends, made by warn. The default position for this with engine off is locked. In 2wd when you start the engine makes it unlock until you shift to 4x4. Not sure what the thump was, could have been the IWE, but the usual problem with them is locking while in 2wd. I assume when you shifted to 4x4 low, you did it in neutral, foot on the brake. If not, especially if tires are spinning a bit, it was the 4x4 system going to 4hi and the front engaging into 4x4. Never engage 4x4 if wheels are spinning. If you try to engage 4lo without being in neutral and foot on the brake, it will go to 4hi, but will not go further.

 

Yes, when I shifted it into 4x4 LOW, the truck was stopped, foot on the brake and shifrter in neutral. It normaly makes a few little click/clunk sounds when the transfer case is shifting from 2wd to 4wd, but this was different. It went into 4wd like it always does, and all was fine until it shifted into 2nd gear, thats when I heard the loud CLUNK from the front end. It was loud enough to where the guys at work that were around the truck were asking me if my truck was ok. It's never doen this before and had me worried, but since then it's never done it again and drives in 2wd on the highway with no problems. The clunk occured while in sticky clay type mud, while towing a 100kw generator (about 5000lbs with a full tank of deisel), truck in 4wd LOW range and having to put my foot into it a bit.