Grinding noise when accelerating

2001 GMC JIMMY
120,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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JIMMYNUT
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No noise when coasting. When accelerating there is a grinding noise. It is similar to a wheel bearing going bad but it is not that. Only makes itself known when the gas pedal is used. Sounds like it is in the front. Latest check up the mechanic had to add two pints to the front differential.
Nov 9, 2017 at 7:40 AM
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MHPAUTOS
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i would be draining the front differential oil into a clean container and looking for contamination. it may be a failed gear set, you will see silvery flex in the oil if it is failing and metal on the catch magnet on the drain plug. Also it can be a broken engine mount and it is allowing the engine to raise up allowing the fan to contact the shroud.
Nov 9, 2017 at 3:19 PM
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STEVE W.
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If the noise is a loud buzz like a bad wheel bearing check the 4X4 front axle actuator. If the vacuum switch on the transfer case starts to leak it can pull in the actuator enough that the locking collar will hit the splines at the end of the axle.
On an 2001 it is under the battery box. To test if this is the issue you can clamp the vacuum line off with the engine off and cold and see if it still grinds. Or on a straight road or gravel/damp grass just shift into four wheel drive high. It will pull the actuator in and if it is the reason the sound will go away.

Nov 10, 2017 at 6:17 AM
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MORRIS
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Yep the motor mount as out in my car cost me $46.00 for a new unit all set up perfect.
Dec 8, 2019 at 7:26 PM
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GRANDMAB5560
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Our 2001 4 door GMC Jimmy 4x4 (our only car) has no gears, won't drive forward or backward with or without my foot on the accelerator, has a horrible loud grinding noise when idle. Could this indicate that the transmission went out?

My wife and I bought this car about 2 years ago. When we bought it, it had a rebuilt engine and all worn parts were replaced. This is our only car. We live in a town that has no public transportation including taxi cabs and is more than 5 miles to the nearest stores, etc. I'm 100% permanently disabled. My wife and I almost have to put my social security retirement income under a microscope to find it. We financially cannot afford to pay $130 to have our car towed 7 miles to the nearest mechanic.
Dec 8, 2019 at 7:27 PM (Merged)
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RASMATAZ
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It sounds like the differential or transmission is out, look under the car while stop and making the noise, if the drive shaft is spinning, the diff is bad, if the drive shaft is not turning the problem is in the transmission.

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Dec 8, 2019 at 7:27 PM (Merged)