I've got a 2010 raptor with the 5.4L that is starting to turn into a money pit. It's actually been the wife's truck since new, and 8 years of mud and air have taken its toll.

We are currently getting a metallic noise coming and going while driving. Only during a steady cruising speed. When you left off the gas, the noise instantly drops. The noise is similar to a chain being dragged on metal, or marbles rolling down a metal slide?

As far as parts or places to check, I have already replaced the following parts within the last year: both front hub assemblies, front and rear brakes and rotors, both IWE actuators, upper control arms, and had the front shocks rebuilt. Sadly, they were all changed for a reason and not just guesses. The wife is just really hard on the truck.

Could this be the chain stretching inside the t-case? If so, is there a difference in t-cases compared to a regular f-150? Or could this be transmission related? I have checked fluid levels, colors, etc on both and nothing was out of the ordinary or low. I'm at a loss on ideas. Any help?

 

Sounds more like an issue with the pinion bearing in the rear axle.

 

I'd have to agree with Alloro, sounds more like a differential bearing issue than it does a transfer case one. When in 2WD, the transfer case chain is just along for the ride, it doesn't care whether you are on or off the throttle.

But the carrier and pinion bearings in your differential load and unload with throttle application, and generally will only make noise a cruising speed unless they get really bad. How many miles on the truck? Has your rear axle lube ever been changed?

 

Back in the day I was a loyal GM owner. I had a 1975 Chevy K-20 with full-time 4-wheel drive. On that particular transfer case (New Process 203) the chain was always loaded and mine had a constant, distinctive drone from the chain for the nine years we owned it. It made no difference if you were accelerating, decelerating, or maintaining a constant speed. Dealing with that truck convinced me to try a Ford.