Zim

So last weekend I was pulling my boat, about 5500lbs total with trailer, down around some lake roads by a friends house, and had to pull it up a pretty good grade on gravel. Before the pavement ended, I flipped to 4wheel High and started going up the hill. No problem engaging, the 4x4 light was on, but it was a pretty slow drive up. I probably should have been in 4-low, but wasn't on a flat surface to stop and go to neutral, and didn't want to lose my momentum on the gravel.

I was putting a good amount of stress on the thing pulling 5500lbs up a pretty steep hill in gravel, and at one of the steepest points the truck made a HUGE clunk. Sounded like a chain jumped in the transfer case (if these even have chains, I don't know the mechanics). This happened 3 times while I was on the steep grade. Finally when I got to a point on the hill that I knew I could restart from with my trailer behind me, I put it in neutral and put the truck in 4wheel low. Had no problems after that.

Any idea what the clunk was? I don't know if it came from the truck being under too much load in 4wheel high, or if it may have been my boat sliding back on the trailer bunks causing a big jerk that just paranoid me. Haven't had any other 4wd issues, but there's only 7500 miles on the truck too.

Any ideas?

Zim

No replies in 3 weeks.

clearnetedm

Not much help here but I remember another fellow poster showed a video of him pulling a 15K trailer with his F150. Some sort of competition. Anyways In that video his truck was making a banging noise as well when he took off and was in 4x4. I remember them saying it was the transfer case letting go or something with the heavy load. Here was the video. Was the sound like that?

Zim

Yes, very similar to that. My truck was definitely under some heavy load in 4wheel high since I was pulling the boat up a steep hill.

FordService

If you're worried, Zim, I'd recommend making an appointment at your dealership so they can look things over. Be sure to come back and let us know when you have news.

Crystal

Zim

Yeah I plan to, just curious if someone else has experienced that. I suppose I DO have a warranty, may as well use it.

Kittrell87

Mine has this same noise when in 4hi and giving any decent amount of throttle or pulling my boat up a hill... Would like to know what it is also and how to fix it.

FordService

What's your truck's model year and mileage, Kittrell87? I'll research some ways to help.

Crystal

Kittrell87

2012, 74k miles. Thank you

FordService

Has your dealership checked this out for you, Kittrell87? Once you've had them diagnose it, I'll be able to step in and assist.

Crystal