hiperf2007

We purchased the vehicle in the title with 158k miles. 4x4. Excellent shape. I started noticing starting at 55 mph up to 65 I am hearing a humming noise. Sounds like its coming from the front. Haven't checked the wheel bearings yet. Wheels are 22" and tires at dated but what gets me confused is when I slightly let off, the noise goes away. Back on the fuel, noise returns. Cruise set coasting down hill the noise goes away. I think I have heard it quickly slowing down also.
The only thing i have done so far is changed engine oil and drained and refilled transfercase. Noise was there before I did any of that. At first I thought it was tires but letting off the gas and the noise going away has me confused.
I have seen other people talk about engine pulleys and tensioners which could make sense due to torque load on the system. If I had to pick a direction, I would head to the front passenger side but I know how noise can transfer. I am going to be looking at everything here in the next few days. Appreciate any input on where to start.
I should also note that the noise isn't extremely loud. Just concerning. I can turn the radio on a bit and drowned it out.

oilcanhenry

Tire noise won't go away letting off the pedal, so it's either your front differential or your wheel bearings. I'd put it up on stands and check for any weird noises, and/or pull your front differential case cover and see what it looks like. I don't know if you bought this vehicle used, it sounds like it, but lots of people don't change the axle lubricants like they should. If it's never been changed, then all the metal that accumulates during the break-in period is still inside your axle, causing wear and tear.

hiperf2007

Yes the vehicle was bought new. I will have to do some more checking. I didn't think it was tires because of that same reason. Would the front cause that type of noise though not being loaded in 4x4 and just floating down the road? Haven't tried in 4x4.
if the front case oil has never been changed i could probably drain and refill but at that point its probably trashed.
Just don't want to chase issues. I have thought the front before with stuff like this and then found the noise was transferring through the aluminum drive up from the rear.

oilcanhenry

It wouldn't hurt to change out the front differential lube and put in some synthetic 75-90w lubricant. I don't know if it will help, but at the age of your vehicle it should be done, front and back. Do it when they are warm/hot. Lots of times you can reuse the cover gaskets too, but they are cheap. You dont know that they are trashed as it could be something else, but at the age of your vehicle they should be done.

repairman54

Just looking at any fluid's color is a big indicator of what's going on inside. Especially at your mileage. Popping off the fill plug is an easy quick check.
Front diff. is super easy with both fill and drain plugs.

hiperf2007

Had some time this past week and dropped the front differential fluid. Dark but pretty much clear of metal. Nothing much to speak of on the magnet. It was also due for tires so those were done. Noise is still there.
No play in the wheel bearings but they look newer. Wondering if they were cheap aftermarket or maybe over tightened.