Humming from drivetrain...

Hello everyone! New here looking for suggestions. I've had a 2007 Tundra TRD 4x4 for about 8yrs. And almost the entire time, especially in cold weather when I drive it there an annoying "humming" sound the resonates throughout the truck.

At first I thought the hubs were bad so I replaced them... nope. I know it's the drivetrain because when I engage four wheel drive it immediately disappears. When I go back to two wheel drive it returns.

Other times I'll engage the four wheel drive system and when I re-engage two wheel drive I'll hear, what I would describe as a "slam" from the drivetrain. During those time I'll start driving and the hum is nearly completely gone. This is all typical on cold days. During summer months it's extremely rare.

One shop put it on a lift to poke around to find the source but the traction control immediately kicks in because the no resistance, resulting in a failed attempt to simulate driving.

Great truck, I love it. No rust Georgia truck and I use it a my primary truck but it's always annoyed the hell out of me. 5.7 227k miles.

Any ideas, anyone? Thanks!!

 

Hmmmm... you just made me notice that I have a hum also. Never really noticed it before for some reason. Thought maybe it's coming from the tires I just put on. I'll be interested in seeing what people think.

 

Needle bearing in the front diff

https://eastcoastgearsupply.com/c-1...hings-2007-up-tundra-and-2008-up-sequoia.html