Vibration/grinding? from 2WD, HELP!

**opcart** · 11-10-2008, 01:46 PM

2001 suburban with 60K miles rebuild transmission. At highway speeds once I let go of accelerator there is a grinding noise like gears coming straight from the center of truck, I tought maybe the rear differential but my mechanic took it apart and saw nothing back there. He does't know what it is. I saw some posts relating to 4WD but mine is a 2WD so no transfer cases here. I am a new guy looking for help, please!

**mehoff400** · 11-10-2008, 02:26 PM

check out your front wheel bearings and see if there starting to go bad

**themexicandoctor** · 11-11-2008, 01:01 AM

continuous when in gear, goes away in second but first is noisy

- last week I changed both U Joints and today I replaced the rear brakes in case there was something dragging like a shoe but instead they were just worn down, to the metal but when I took it for a test drive the noise was still there - *&^%$

- maybe I need to get my tranny rebuilt - just a grating noise that disappears in second, I had two more tranmission rmechanics drive it today without the grating and they said it sounds fine, the trans is shifting okay, and that the noise is from the exhaust but that noise is a different one - the trans oil smells good, looks good - the mechanics who are working on it said just drive it until it blows,

it has a 100k on it - the trans & the diff havent had a service in at 40k miles since I have owned it,

should I drain the oil and loook for shavings from the trans

and should I do the same for the diff or just leave them both?

**JMoney02** · 11-12-2008, 12:36 AM

OpCart,

Yes, check bearings, any material between front pads and rotors? Can you see the rotors without the wheels removed, if so, check for score marks. You said the noise is in the middle of the vehicle? Sure its not from the rebuild? Did it do it before it was rebuilt? Did the noise come all of a sudden? Gradually? Check the front wheels, jack the front and put your hands on the top and bottom of the tire and pull in and out, this will show if the bearings are loose, put hands on sides and pull/push in and out to see if tie rods are bad, make noise(may). I would also do a visual check for any obvious things loose underneath. Warranty from the trnas shop? If so, ask them to check? I would start there.

Jeff

**JMoney02** · 11-12-2008, 12:45 AM

Originally Posted by themexicandoctor

continuous when in gear, goes away in second but first is noisy
What about the rest of the gears? Noisy also?

- last week I changed both U Joints and today I replaced the rear brakes in case there was something dragging like a shoe but instead they were just worn down, to the metal but when I took it for a test drive the noise was still there - *&^%$
What happens when you manually shift, nosie still there? Try this and see.

- maybe I need to get my tranny rebuilt - just a grating noise that disappears in second, I had two more tranmission rmechanics drive it today without the grating and they said it sounds fine, the trans is shifting okay, and that the noise is from the exhaust but that noise is a different one - the trans oil smells good, looks good - the mechanics who are working on it said just drive it until it blows,
For the miles it may be the case and not break for sometime, can you wait until then? Do you have a backup vehicle?

it has a 100k on it - the trans & the diff havent had a service in at 40k miles since I have owned it,

should I drain the oil and loook for shavings from the trans
Do you want to spend the cash now? If so, it will tell some story if there is a problem.

and should I do the same for the diff or just leave them both?

I would change this fluid now, its not your problem with the noise, I believe its the main shaft making the grinding noise, could be the planet gears are worn badly. I would let it go for now unless it become unbearable, then get the rebuild, can save up some cash until then. What do you think?

Jeff

**retired** · 11-12-2008, 01:19 AM

Sounds like the planetary gears in the trans, you'll be getting that trans built again.

**EagleTalons** · 11-12-2008, 01:21 AM

Could you possibly record this sound so we could hear it?

**JMoney02** · 11-12-2008, 01:31 AM

Now, thats cool. I remember when a customer put a recorder under his hood to record a sound that would not show up when he would bring it in to check out. Drove it one test drive and the bolt for the
harmonic balancer sheared in the driveway right after the test drive on the road, pushed it into the bay and repaired it. So, great idea if you can swing it.....

Jeff