My 2019 F350 CC LB with the 6.7 and 77K miles has developed a new noise that I am having trouble diagnosing. I hear this mostly at highway speeds if I am coasting down hill at 75-80 mph I have a pretty loud bearing type noise that mostly goes away when I apply the throttle. It is loud enough that my 11 year old son asked what the noise was. I can feel it if the floor of the truck, it feels like a failing bearing. Strangely the noise sounds up front but it could be resonating from the back of the truck I guess. It is bad while coasting adding throttle makes it go away. Since I have become more sensitive to it I can hear it at 45mph as well but seems to go away between 50-70mph. When in the drivers seat, the noise does sound like a front wheel bearing, but when I touch the throttle it goes away.

I drained some fluid out of my M275 and checked the magnet and there was nothing very alarming, no glitter just a little buildup on the magnet. I changed the diff fluid about 30K ago. I also drained the T case fluid and did not find any metal in the T case. Visually the carrier bearing and all U joints look good, no driveline slop. Nothing in the front axle is turning, the hubs are not locked.

I tried to run the truck on jack stands, and listen to the driveline, but difficult to do alone and with traction control I cant run the truck up to speed.

Has anyone else fought anything like this? I have a 1,500 mile camping trip coming up in 2 weeks and I wont be taking this truck if I can't figure this out.

Thanks guys

 

Nothing comes to mind


maybe a recording will stimulate some participation


just a general comment and not associating anything you said with this comment..but in my lifetime power off noises especially down hill have been either cracks in starter flywheel or loose bolts on starter flywheel . Has the transmission been disconnected for anything like the upper engine oil pan gasket fix…if so..some follow up work might be needed.

 

Thanks for the thoughts, I have owned the truck since new. It has never been to a dealer for any work, trans has never been out but I will add your comment to my list of possible causes.

Thanks

 

Does anyone know how to disable to the traction control so I can run the truck up to speed on jack stands?
Thanks

Edit: ABS fuses in manual, 32 52 and 59. I will try pulling these and running the truck on stands.

 

I'm not a mechanic nor do I play one on TV. You mentioned changing the diff fluids and I remembered something about possibly needed to use and additive.
Sorry, it's been a while since I read that post so I can't add anything more.

 

Perhaps try one of these....

STEELMAN 06600 ChassisEAR Electronic Squeak and Rattle Finder

https://www.amazon.com/dp/B000IHIAES/?coliid=IIA3Y7XCY1DG3&colid=2XFV71Z7JQ9EI&ref_=lis t_c_wl_lv_ov_lig_dp_it&th=1

 

you can press and hold the traction control button for 10secs to disable the system and run it on the stands.

 

Update for anyone in the future. I have determined I have a bad pinion bearing in my Dana M275 at 77K miles. I have a two piece drive shaft, so I removed the rear section and ran the truck up to speed just spinning the trans/tcase/and drive shaft to the center support bearing and had no noise.

Hooked the driveline back up and ran the truck up to highway speed the it was very loud. The pinion area of the housing got hot just at idle speed and a wooo wooo wooo noise could be heard as speed increased. I drained the fluid and the fluid was full of very very fine metal particles that are suspended in the fluid, so small I am not able to feel them between my fingers.

 

That's what I figured. As soon as you said the noise changed with throttle input it immediately sounded like differential failure.

 

Anytime a noise is heard that changes with load is usually caused by worn pinion bearings. Had the noise remained constant the moment the vehicle is in motion, the likely culprit would be your carrier bearings. You obviously intend on having this issue addressed so it would be wise to simply replace everything while it's all apart. The measurements will all need to be reset anyways, in order to gain access to and replace the pinion bearings.

 

Agree, I was a bit in denial that my M275 bit the dust at such low milage. I always wonder if there is something that I could have done to contribute to a failure.

I changed the fluid to Valvoline synthetic about 30K miles ago
It has Carli full leaf pack, so pinion angle could be slightly different, but it has never had a vibration
I run 37" tires
I tow my camper long distance but it is 12k at most

Maybe it was luck of the draw and I just got a bad setup or a bad bearing, not sure. Debating on how I want to tackle this repair. I have set up some myself for rock crawling, but this is a different ball game.