Just joined and need some help. I have a 2015 F150 4x4 with 1800 miles on it and when I’m driving up an incline in 4x4x low, you can feel the drivetrain start to “bind” then at the top of the incline it makes a loud “pop” similar to the sound a chain makes when it breaks and you can feel something “give”.

The incline doesn’t have to be really steep enough for 4x4, the wheels aren’t spinning and it takes about 20 yards for it to build up the “bind”. There is a small incline at the farm and it does this every time without fail both forwards and backwards. The “pop” is loud enough that you think you just broke something.

First trip to the dealership, they couldn’t duplicate. Second trip I had to wait over 2 hours to meet with the service manager. Problem is they don’t have any “offroad” area to test the truck. Finally found a ditch on the side of the road and was able to consistently duplicate the “pop” and something “give” in the front end. The incline is apparently not long enough for the “pop” to be as loud as it would at the farm but there is definitely a "pop".

Service manager agrees there is a problem. He hooks up his computer to it and we drive up the ditch and duplicate the “binding” and “pop” but the computer doesn’t tell him anything. I leave the truck and he calls Ford to research. Now they tell me this is “normal”.

I’ve had more 4x4’s than I can count and currently have a F250, old model Tundra, new model Tundra and a Jeep Rubicon. None have ever made any kind of noise remotely similar. The new Tundra and Jeep both have traction control and don’t make any noises or “binding”.

The problem is that I’ve added a 2” leveling kit and 34” tires and I can see something breaking in the near future and having Ford blame it on the modifications. The truck was having these problems before any mods.

Thanks for reading this long post and any advice would be appreciated.

 

On dry ground in four low, sounds normal to me, especially if things haven't fully engaged when you start up the incline. My 05 will bang into 4 high if you don't let it fully engage prior to putting a pull on the drive-train.

 

Thanks, but everything is fully engaged. I put it in 4 low whenever I get off "road", i.e. driving around a field. 4 low is engaged at least 10 minutes or so before I get to any "incline". And the "pop" sounds like breaking chain or a firecracker.

 

Does it do it in 4 high? Do you really need 4wd in this situation? You are going to get binding and popping in 4wd any time you have good traction.

 

Yes it does it in 4wd high and I don't have good traction. (i.e. sandy field, wet muddy grass)

 

Based on your description, I'd be counting teeth on ring gears front and rear. If different (ratio) gear sets were somehow installed front and rear, it would take a while to bind up.

 

Are all 4 tires the exact same size?

 

Same size tires.

 

It is the weight shift to the rear of the truck, normally the front will drag the rear somewhat allowing for the 4x4 to unwrap gradually. It probably doesn't do it going back down the hill. Because of the weight shift the tires are traveling over the ground at different rotational speeds in respect to the distance traveled. The I told you so_ or I told you not to do it comes into play here. U can probably rule out the truck shifting back to 2x4 due to a malf, low vacuum would work the opposite way but inspecting the vacuum pump if you have a ecoboost, they have been known to corrrode ?.

 

Probably cv joints popping. Take off the level kit and see what it does.