2001 GMC Jimmy metal grinding sound

[rmjohnson1]

I have a problem with my 2001 GMC Jimmy in that it will sometimes make a very loud metal grinding sound that increases with speed. It sounds like it is from the front of the vehicle. When I slow down to 10-20mph it becomes a staccato like clunks like a metal object up against bicycle tire spokes. So the faster I go the faster it gets. When I get up to about 50-70mph it will then sound like a loud whine. It also shakes the vehicle. When I slow down and come to a stop it will make a loud clunk and then stop. Sometimes is starts back when it get up to 20-40mph. Sometimes not. Some days it will occur and some days not. A mechanic is currently working on it now and says that the universal joint looks good and that the front differential was drained to look for metal fragments but that turned out OK too. So right now he says he doesn't know what the problem is. Any ideas?

 

[Molson02536]

I have a problem with my 2001 GMC Jimmy in that it will sometimes make a very loud metal grinding sound that increases with speed. It sounds like it is from the front of the vehicle. When I slow down to 10-20mph it becomes a staccato like clunks like a metal object up against bicycle tire spokes. So the faster I go the faster it gets. When I get up to about 50-70mph it will then sound like a loud whine. It also shakes the vehicle. When I slow down and come to a stop it will make a loud clunk and then stop. Sometimes is starts back when it get up to 20-40mph. Sometimes not. Some days it will occur and some days not. A mechanic is currently working on it now and says that the universal joint looks good and that the front differential was drained to look for metal fragments but that turned out OK too. So right now he says he doesn't know what the problem is. Any ideas?

Could be a bad front wheel bearing if your ABS lights are on or a bad CV joint and even a bad brake pad that has separated. Also from the sounds from what you described is a cracked brake rotor.

Keep us posted on what the issue was.

 

[rmjohnson1]

OK. thanks for the info. Will let u know what happens. By the way, I talked to another mechanic and he said that when the sound occurs, switch the vehicle into neutral and turn the truck off. And that this will let me know if it is from the wheel bearings, brakes, etc; versus the transmission, trasfer case, or front differential. Anyone else think this is a good idea?

 

[rmjohnson1]

Well, the mechanic who is a gmc truck dealership said he couldn't find the problem but that it wasn't making the noise now. So he told me to bring it back in if the problem reoccurs. Oh yeah and here's your bill for $420!! Needless to say, I won't be taking it back there again.

 

[Molson02536]

Well, the mechanic who is a gmc truck dealership said he couldn't find the problem but that it wasn't making the noise now. So he told me to bring it back in if the problem reoccurs. Oh yeah and here's your bill for $420!! Needless to say, I won't be taking it back there again.

For the vibration in your front end, it could be a worn ball joint, idler arm or even just the tires being old and needs to be balanced. Start with the things you can do and grease all the front steering linkage and suspension fittings with http://www.pennzoil.com/documents/Pennzoil Marine Premium Plus Multi-Purpose Grease.pdf, Yes it cost more, but will last much better.

The marine grease will fill up all the void from worn parts and see if the vibrations go away and tighten up your steering play. Once that has been done, inspect your tire pressure and adjust accordingly 32-36PSI. Depends on your ride comfort you like, 32 softer 26 firmer.

As for the clunking sound, common area that is now that causes this is a worn hood hinge bushings. As the Jimmy vibrates the worn hood hinge pins bang against each other causing the noise. Here's the full text of the TSB that refers to the hood rattle. Open your hood and hold on to either corner of it. Rock your hood back and forth and if it's the washer you'll hear the clunk. It's a dealer only part (unfortunately) is a tiny washer that fits on your finger tip. It's aboaround 5-6$.


Hood Hinge Rattle (Install Spring Washer) #01-08-63-001A
Hood Hinge Rattle (Install Spring Washer)

1995-2002 Chevrolet and GMC S/T Pickup and Utility Models (Plant Codes 8 and K)

1996-2001 Oldsmobile Bravada

This bulletin is being revised to add the 2002 model year, plant codes, and update labor time information. Please discard Corporate Bulletin Number 01-08-63-001 (Section 08 -- Body and Accessories).
Condition

Some customers may comment on a rattle coming from either or both front corners of the instrument panel near the hood hinge areas. This noise may often be mistaken for a loose shock absorber. The rattle may be heard when driving over rough roads and is most noticeable when the road surface creates a side-to-side vehicle motion.
Cause

Excessive clearance at the hood hinge attaching bolt may cause this condition. The excessive clearance allows the hood hinge to make metal contact with the hood hinge bracket, which produces a rattling noise.

Correction
Important

For additional information, see the Body Front End subsection of the Body and Accessories Section of the appropriate Service Manual.

1. Remove the hood hinge attaching bolt (1).
2. Install a spring washer (2) on the bolt as shown in above illustration.
3. Install the bolt.
Tighten

Tighten the bolt to 25 N·m (18 lb ft).

Part number is 12383460