Intermediate humming at high speeds

I have a 2010 ACLB 4.0L 36,000 mi at stock height with 265 70 17 All terrains. Above 60 mph up to 80mph I can hear and feel a humming noise. It will hum for a about a half second and then cut out for about a half second and repeat. The faster you are going the noise occurs slightly faster. Seems like wheel bearing symptoms but putting load on either side doesn't seem to do anything and the noise isn't constant as well as its very low miles. The truck is driving fine otherwise. Any thoughts would be greatly appreciated!

 

Does it go away in 4 high? (you can switch into 4 high up to 60mph)

 

Good idea Ill have to try that.Are you thinking Needle bearing? thanks

 

Its possible and its an easy test for sure. Usually its around 40mph that it starts to vibe so its possible its something else.

 

Took it for a ride. The vibe is definitely more noticable starting at 65mph. Only pushed the truck to 65 in 4 hi but still felt the vibe.

 

Hmm, when was the last time you greased U joints?

 

about 9k ago. Doing an oil change soon so ill do it then and spin the bearings while its up on the lift. Previous owner did every 5k before I bought it but last oil change i did i was recovering from hip surgery so wanted to just do oil change...

 

As long as they have gotten some love you should be good there. Undo the two bolts for the carrier bearing and support the drive shaft and give the CB a good spin to feel if that bearing is going out. (easy things first right)

 

Thats right, work smarter not harder! I figure I'll be okay until it gets worse and then I can really figure out whats going on. Thanks for the help!

 

Not trying to thread jack but what grease is everyone running on the U joints?

 

I use good ole red n tacky on pretty much everything with a zerk (outside of SPC ball joints and poly bushings).

Realistically for u joints, fresh grease of any standard kind, hell even marine, is better than old grease.

 

Right on. That’s what I’ve got loaded in the grease gun. I figured it was fine but thought I’d double check. Thanks for the input!