I have an intermitant vibration in my gas pedal. It is more like a buzz, that lasts for 1-2 seconds. It then goes away for a few minutes, and then returns. On a 1/2 hr commute, it happens 5-6 times or more.
This happens usually once around 45 mph (3000 rpms), while accelerating to 70 -75 mph. Then is happens around 72-73 mph, with sometimes even up to 78 mph. In 4WD hi, it seems to be more frequent (1-2 second vibration every 30 seconds). When I let off the gas, it goes away.
It started about 2 months ago, and only happened while towing my boat. Now it has been doing it all the time.
2003 Tahoe, Z71 4WD
160,000 miles
Original drivetrain
265/70/16 standard size, with approx 40,000 miles
In thought the issue was either the u-joints or rear differential. I dropped the rear driveshaft, and both u-joints were perfect - free, with no play (still factory). Balance weights were still in place. It was time to change the rear diff fluid anyway, so I inspected the rear end and other than a little play everything looks great with absolutely no metal on the magnet. All tires to 37 psi as always. Other than oil changes, nothing has changed in the last 12 months.
I went 1 whole day without an issue, and now it is back.
Any ideas? I can only feel the vibration in the gas pedal, and hear a slight sound during this 1-2 second event. Nothing in the steering or seat.
I can't see how it is the front driveshaft u-joints, as it should not spin in 2hi. Transmission? Transfer case?
This happens usually once around 45 mph (3000 rpms), while accelerating to 70 -75 mph. Then is happens around 72-73 mph, with sometimes even up to 78 mph. In 4WD hi, it seems to be more frequent (1-2 second vibration every 30 seconds). When I let off the gas, it goes away.
It started about 2 months ago, and only happened while towing my boat. Now it has been doing it all the time.
2003 Tahoe, Z71 4WD
160,000 miles
Original drivetrain
265/70/16 standard size, with approx 40,000 miles
In thought the issue was either the u-joints or rear differential. I dropped the rear driveshaft, and both u-joints were perfect - free, with no play (still factory). Balance weights were still in place. It was time to change the rear diff fluid anyway, so I inspected the rear end and other than a little play everything looks great with absolutely no metal on the magnet. All tires to 37 psi as always. Other than oil changes, nothing has changed in the last 12 months.
I went 1 whole day without an issue, and now it is back.
Any ideas? I can only feel the vibration in the gas pedal, and hear a slight sound during this 1-2 second event. Nothing in the steering or seat.
I can't see how it is the front driveshaft u-joints, as it should not spin in 2hi. Transmission? Transfer case?
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