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Transmission Noise

2004 GMC Envoy XUV, V8, 2WD

My fiance’s transmission makes a whirring/squeaking noise in park and neutral. This noise goes away when the car is put in drive or reverse. Doesn’t seem to be making any noise while driving. Fluid is at the recommended level, nice pink color, not dirty at all.

Also forgot to mention. The speedometer/speed sensor? is on the fritz. It moves when the car speeds up but usually won’t indicate zero. Most of the time when the vehicle is parked it shows 40 or 50 mph. (Law enforcement officers can relax, we just use a GPS to see how fast we are going)

What makes you think that the noise is from the transmission? There are lots of things that can whirr & squeak and many of those will change what they do when you change the load on the engine - say, by putting the transmission into gear. I’d be looking at your serpentine belt and pulleys.

Is the speedometer accurate beyond 40 or 50? What does it do when it is registering something? I’d be inclined to think that is an instrument cluster problem.

Initially thats what I thought too, belt, pulley, compressor, power steering pump? While the car was making the noise we popped the hood and tried to localize the sound. The sound is barely audible at the front of the vehicle hood open or closed. Once we got down on the pavement we could hear it coming from behind the engine beneath the vehicle. Equally loud from the driver/passenger side. Maybe a pump or bearing in the transmission? Still goes away when put in gear.

As far as the speedometer it moves up and down with the change in vehicle speed, just the zero point changes. Sometimes we’re stopped at a light and it’ll say 50 yesterday parked it was at 30. A ten mph increase in speed on the GPS gives like a 15 or 20 mph increase on the cars speedo as well.

We’ll probably go to the shop tomorrow, keep your fingers crossed.

Just got back from the transmission shop the put it up on a lift. From the noises they could hear they think that it could be the torque converter getting ready to go. It was definitely coming from the transmission. Any ideas?

On a lighter note looks like the speedometer may just have a bad stepper motor in the gauge cluster. That should be a pretty inexpensive fix.