1st gen hum

Hello all,
I’ve got an 02 tundra 4x4 has a hum/droning sound coming from what sounds like the front end. Had the CV axle and needle bearing replace with egs bushing, front , rear diff and transfer case fluid changed. No play in the hubs for wheel bearings. Typically around 60-65 you hear a pronounced hum let off the gas it quits get back on it starts. If you turn O/D off and on it’ll stop and start with O/D off trans fluid was clean. This thing is driving me absolutely crazy tracking it down anyone have any insight on the issue ?

 

If having the OD on or off changes it, like for real changes it, then it stands to reason it’s a transmission issue.

 

Did this start before or after the maintenance you just listed?

Droning (wahwahwahwah or wubwubwubwub at higher speeds) is often wheel bearings, but can also be output shaft bearing or pinion bearing to name a couple. Your year of Tundra (2000-2002) also came with the transmission that had a weak planetary gear which likes to grenade (EDIT: Looks like KNABORES beat me on the OD trick... )

But sticking with the most common, have you done the classic test for wheel bearing play every home mechanic should know?

Is your truck lifted, either with strut spacers, or a proper suspension lift? (If yes, we need details)

Does it happen if you're up at speed only in 2HI, or also in 4HI? (You can drive in 4HI at that speed; but you shouldn't be trying to make turns past 11 o'clock - 1 o'clock on pavement when it's engaged, and you must engage 4hi below 35-40mph or something, else it'll fail).

@455h0le_dachshund what was your droning sound again?

 

Angry diffs is the short answer.

The longer answer is mud and water in the leaking diffs, which weren't set up properly when regeared, pinion bearing went bad, gears got all chewed up, ecgs bushing somehow became unseated, and wheel bearings were bad. I think that covers it.

Hopefully OP doesn't have even close to the laundry list of problems I did. $$$$

 

@shifty` started before the maintenance wheel bearing test is passed no play in the wheels no grinding on the lift when I turn them. No lift and it still has the issue in 4hi haven’t tried making a turn since it occurs at around 62mph. As far as the sound it’s just a constant “hmmmmmmmm”. May very well be the planetary gears kind of stumped me when the fluid was in good shape but may very well be the beginning stages. Thanks for the insight

 

My humming turned out to be front wheel bearings, even though they checked out fine on the truck. Once I pulled the spindles, both were obviously bad.

 

Hoping

yeah I’m hoping the list isn’t that long CV had a good bit of play needle bearing was shot replaced with EGS but the needle bearing hasn’t grenaded yet. Maybe time to invest in some steel man chassis ears to see if it’s trans or front diff thanks guys

 

Wait, is it more of a constant hum, or is it a pulsating sound?

I used the wahwahwah and wubwubwub on purpose, only because that’s what it sounds like to me. But if it’s more of a droning hum, you may need to be looking at the driveline. U-joints first, carrier 2nd. On the 4WD version of our trucks you need to grease all driveline components every 3k-5k miles with moly-fortified NGLI 2. Something many people neglect, it’ll fry the u-joints at best, which then take the carrier and other things with it after too long of vibrating. And you get fun stuff like CLUNK when stopping/going, and other crap.

 

Constant hum at 62mph but no vibration

 

And it’s not the tires?

 

Yeah, if the hum isn’t pulsing, and it doesn’t go away toggling OD, it’s probably not trans or a standard bearing. I’d be eyeballing u-joints first, and checking the rubbers on your carrier. Especially if you aren’t lubing your driveline at least every 8k-10k miles.

it’s easy enough to test for play in u-joints. Any quality driveline specific shop (I wouldn’t use a chain shop or stealership to do the work, I’d you don’t want to, always driveshaft shop, they’re cheaper) can diagnose, often free, and replace for minimal parts and labor.
OEM driveshafts and u-joints and carrier bearing on our trucks were made by Spicer/Dana. Recommend replacing with Spicer.

 

My hum was from about 45mph+ and it slowly stopped when I would let off the gas. Then the wub-wubs would start.

Not the best videos, but that's all I got. Noise starts about 8 seconds into the first video. Stops at 50 seconds, then wub wubs start.
https://youtube.com/shorts/hwiV8TddMDA?si=aZ2ZG6TnhHnF9vna
https://youtu.be/ePTwA2TvK58?si=hPDUw_eiSHZKPOKa
Very pronounced whine/hum at 13 seconds in second video.

 

Brand new set of tires less than 5k but I’ll rotate them and see if it changes