satiger

iTrader: (1)

This is driving me crazy.

I hear this humming sound when hit 70mph and I am on the gas. However it lasts till 73mph or so and go away!. Below is the pattern I observed;

1. On gas (accelerating), when hit 70mph (not even 69 mph) I start hearing humming sound. It will last till 73mph and goes away. Not able to pin point the source. I feel it is originating somewhere closer to transmission shift.

2. Decelerate from above 73mph and no gas given, when hit 70 I don't hear the sound. Press the gas pedal, I hear.

3. Set the cruise at 70, I hear.

4. The hmmmm sound appears only between 70-73 mph speed and while on gas.

What is this sound?. What is the source?. Any lead?.

LexRex

How many miles on your truck? Any lift?

Could be a variety of things. I'd start with making sure your U-joints are lubed. When you crawl under there to lube them, you can check your driveshaft U-joints for play. Also look for play where the driveshafts attach to the transfer case and differentials. You can have a little bit of rotational movement of the driveshaft at the differentials and transfer case, but otherwise they should be very tight.

Jack up each front wheel and check for any play when you wiggle the tire with hands at the 12 o'clock and 6 o'clock positions. You're checking the wheel bearings when you do this.

Ensure proper fluid levels in the differentials and transfer case.

Those are the easy things to do if you have a jack, a dry parking spot, and an hour of free time.

satiger

iTrader: (1)

Thanks LexRex for the leads. I will check those and report back.

Just curious, wouldn't a faulty wheel bearing causes increase in noise with vehicle speed?.

Edit: forgot to mention , vehicle has 126k miles and no lift with Michelin tires.

kamlung

iTrader: (8)

i have a similar noise that seems to go away at a certain speed too... if it was wheel bearings, i thought you would always hear it under load... i've got <75k miles...

but with all this damn snow we have been having, i haven't had a chance to get under the car... might have to wait until spring...

IanB2

Being that it's coming from near the shifter area, also check out your exhaust system while you're under there, maybe a worn out gasket at one of the connections allowing a leak? Just a wild guess.

southrnman

Satiger - I have the same issue with my '13 GX. It's been in the shop (dealer) for a month now, and latest is that it may be a "feature" of all GX models. I only have 25k on her, and I actually had her in shop at 15k miles for this issue. The dealer investigated initially for weeks, and ended up replacing the transfer case fluid and the hardware itself. Car returned and noise was no better. I am meeting with regional tech rep next week and will drive a variety of GX models with s/he. Dealer thought it might be tire wear, replaced them and no change. The forum is full of many leads, but none that I would consider strong. Have you pressed the dealer on this issue? I am most concerned about the overall experience of driving a car with this annoying noise as well as the impact to resale if this issue gains more attention.

new2012jee

its not driveshaft hum?

chiph9

I may have this as well. The dealer has a remote microphone that they attached to various parts in an attempt to locate it, but were unsuccessful (not a wheel bearing, not a driveshaft, etc)

In my case, it sounds like it's coming from the passenger floorboard area.

I had differential and transfer case fluids changed last year. They say they greased the driveline at that time, but I haven't verified it myself.

Chip H.