Driveline hum - need help

[chrissurfr]

Hi all,

I have been chasing a vibration/hum that no one can seem to figure out from my driveline. I have a 2017 trd pro with 26k miles on it. I’ve taken it to the dealer with no luck. No other shop has really had much luck either. It seems to happen about 60% of the time.

It is a metallic hum/vibration that seems to be coming from the center, sometimes the rear of the car. Though, it is hard to really pin the direction sound down because of resonating in the cabin.

Speed Characteristics:

• On pavement the noise is intermittent and present about 60% of the time.
• Hum comes on around 33-35 mph and is there between 30-40mph
• It will be present and sometimes go down to 20mph.
• The noise is more present at lower speed if I am in sand or on a softer surface.
• The hum does not change pitch or pulsate with different speeds but it will be louder sometimes at different speed between 30-40mph.

RPM/Throttle/2WD/4WD Characteristics:

• The noise is present in 4wd and 2wd.
• Noise is present on throttle, off throttle, coasting, and if put in neutral while coasting.
• It is not RPM dependent it is only speed dependent.
• Noise stays the same if I swerve left or right. Does not change pitch tone or volume if I swerve left or right.
• Noise seems louder and more prone to happening on cold days.

Repairs taken to date:

• Needle bearing was replaced with ECGS and the noise is still there.
• Rear carrier/differential was replaced under warranty and that did not solve it.

Dumb things I’ve done that may have contributed:

• I’ve grinded the t-case once or twice switching gears. (t-case gears?)
• I have wound up the 4wd system once on pavement to where the drivetrain popped when turning. (front diff gears?)
• I’ve jumped the truck once – though nothing too crazy. (axle problem from landing?)

Any ideas?
Transfer case?
Driveshaft? Ujoint?

 

[JP421]

Do you feel a vibration in the gas pedal?

At around 40 mph I have a vibration in the drivetrain that comes and goes, can really feel it in the pedal. At first I thought it was the tires but I've swapped to my summer wheels/tires and it is still there.

 

[ahtoxa11]

Do you have aftermarket skid plates? They can resonate some of the sound back into the cab under some conditions. Mine has resonance/vibes at specific speeds (higher than yours) that started after skids were installed.

 

[chrissurfr]

Do you have aftermarket skid plates? They can resonate some of the sound back into the cab under some conditions. Mine has resonance/vibes at specific speeds (higher than yours) that started after skids were installed.

no - this was present before any mods went on.

 

[chrissurfr]

Do you feel a vibration in the gas pedal?

At around 40 mph I have a vibration in the drivetrain that comes and goes, can really feel it in the pedal. At first I thought it was the tires but I've swapped to my summer wheels/tires and it is still there.

no sir

 

[ahtoxa11]

no - this was present before any mods went on.

Have you driven other 4runners to compare their noise with yours?

 

[ahtoxa11]

Have you looked into the heat shields? Those are more of a rattle, so perhaps different than what you describe.

Otherwise, since you did jump the truck, I'd honestly have the frame checked, just to be sure. It's extreme perhaps, but you may have bent something that is affecting driveline angles and causing vibration.

 

[thennen]

Regarding the skid plates, did you try removing them and driving? The fact that it doesn't change pitch makes me wonder if it's an airflow thing versus a mechanical thing. Heck, even remove the spare and go for a drive, or maybe the spare needs snugged up. Maybe something else that might be getting significant airflow over it that could cause vibration.

 

[Jivewalker]

Tires, wheel caps, wheel well liners, washer hose on underside of hood, grease spider joints / slip yokes?, heat shield loose?, rock on top of skid plates or somewhere, loose exhaust, chain on spare rattling, friend hid vibrator somewhere underneath and wired it to 12volts ignition circuit?