Grind noise - differential?
Thread Starter
5th Gear
Joined: Sep 2008
Posts: 5
Likes: 0
Grind noise - differential?
I have a '93 C4 automatic.
When the car is started, and placed in gear, and rolls a few feet, there is a brief "grind" noise coming from the rear underside. It only lasts a brief second, and as long as the car continues to run, the noice never repeats, regardless of forward/reverse motion or shifting.
The sound happens every time it's first started and rolls, but ONLY happens at that time.
I assume this is NOT the transmission, as the sound is originating from the rear of the drivetrain. My only logical guess is the differential.
Anybody with similar experience? Is this a lubrication problem, or do I need to replace parts?
Thanks!
When the car is started, and placed in gear, and rolls a few feet, there is a brief "grind" noise coming from the rear underside. It only lasts a brief second, and as long as the car continues to run, the noice never repeats, regardless of forward/reverse motion or shifting.
The sound happens every time it's first started and rolls, but ONLY happens at that time.
I assume this is NOT the transmission, as the sound is originating from the rear of the drivetrain. My only logical guess is the differential.
Anybody with similar experience? Is this a lubrication problem, or do I need to replace parts?
Thanks!
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I think that's your ABS system's self test you hear which is normal to hear......should come on automatically @~4mph...test takes a second or 2 then the noise goes away until the next time you start the car.
Pro
Joined: Feb 2006
Posts: 671
Likes: 10
2021 C4 of the Year - Unmodified Finalist
the noise
I had the same thing with my 93 vert six speed. Just as the drive side of the power train torqued up I had this metallic noise from the left rear hub.
I mentioned it my mechanic, I thought for sure it was a U joint or bearing. He said it wasn't. I'll be damned if I can recall what he said the problem was, but it wasn't serious cause he said not to worry about it. I have since sold the car, the new owner has not had any problems. In fact he doesn't hear the noise.
The brake ABS self test is a different noise, not mechanical; more electro servo type of sound. If it were the ABS self test you would feel a SLIGHT kickback in the brake pedal as it runs through the POST (power on self test)
Hope that helps, sorry I can't remember the diagnosis.
I mentioned it my mechanic, I thought for sure it was a U joint or bearing. He said it wasn't. I'll be damned if I can recall what he said the problem was, but it wasn't serious cause he said not to worry about it. I have since sold the car, the new owner has not had any problems. In fact he doesn't hear the noise.
The brake ABS self test is a different noise, not mechanical; more electro servo type of sound. If it were the ABS self test you would feel a SLIGHT kickback in the brake pedal as it runs through the POST (power on self test)
Hope that helps, sorry I can't remember the diagnosis.
Advanced
Joined: Aug 2006
Posts: 96
Likes: 0
From: Spokane Washington
It took me a couple of months to track down that kind of a sound. It finally got worse and I was able to see some deteriation on the outside u-joint of the drive axel on the drivers side. I did the job just a couple of days ago. Gary
Thread Starter
5th Gear
Joined: Sep 2008
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Thanks all.
I never have my foot on the brake when the sound occurs, so I haven't tested for that slight kickback. It happens when I'm just starting to apply the gas. Never continues as long as the car keeps running.
I'll listen again and try to feel the brake pedal. Your description of the ABS self test sure sounds plausible, I'll keep your advice in mind.
Thanks again -
I never have my foot on the brake when the sound occurs, so I haven't tested for that slight kickback. It happens when I'm just starting to apply the gas. Never continues as long as the car keeps running.
I'll listen again and try to feel the brake pedal. Your description of the ABS self test sure sounds plausible, I'll keep your advice in mind.
Thanks again -
Thread Starter
5th Gear
Joined: Sep 2008
Posts: 5
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I think it was the ABS test!
I think you were right about the ABS test.
I've kept one foot lightly touching the brake pedal, and exactly at 4mph, the predictable grind noise.
For something so normal and by-design, I am surprised how loud it is. Never had a car do this.
But, at least I can stop worrying. Thanks again guys-
I've kept one foot lightly touching the brake pedal, and exactly at 4mph, the predictable grind noise.
For something so normal and by-design, I am surprised how loud it is. Never had a car do this.
But, at least I can stop worrying. Thanks again guys-
