ABS light on the dash is illuminated (I know the sensor in the front passenger side is bad)
No other codes in the OBD
The sound is intermittent - maybe only 40% of the time when I’m backing up.
I get in and start it up. I put my foot on the brake and shift into reverse to back out of my driveway or a parking spot. I feel it settle into gear, give it a couple seconds, and everything seems just fine. I slowly lift my foot off the brake and suddenly there is a horrible - and very loud - REEEEEEEEEE sound.
I’m not sure where it is coming from. I hit the brake and throw it back into park and the sound goes away. I put it back into reverse and slowly back out without a problem.
It is very loud and will startle other passersby in parking lots. It’s been happening for about as long as I’ve owned it (a couple years), but there were so many other pressing issues to deal with that I’m finally getting around to figuring this out.
I’d like to save the $75 diagnosis fee at my mechanic if possible, but this is my last step before I bring it over there.
There was a recall on Chevy Tahoes from some time around then (which I bet extends to your car) for vehicles in salty conditions. Oddly enough, Wisconsin didn’t count. Anyways, the salt corroded some sensor or part of the ABS system and after you moved the car about 40 feet it made this horribly loud vibrating sound. I’m not sure exactly what the sound was (since it’s been so long since I heard it and read the recall). It might have been the ABS testing/resetting itself.
Eitherway, if the records go back far enough, you might see if you can find a database where you can punch in your VIN and see if there’s a recall on the brake system.
Also, is it electronic or sound like it’s made by something electronic? When you said ABS and Suburban and I saw you location, I thought about that recall. You might just have worn out rear brakes and they’re trying to adjust themselves when you back up (even thought they’ve already adjusted as far out as they can go).
You make it sound as if you only hear this when you are initially moving in reverse, is that correct?
Have the rear drum brakes ever been checked or replaced? How long does it sit between drives and is it outdoors or humid? I suspect that rust is forming on the rear brake drums or the shoes are totally worn out and sqreaking metal/metal. After it moves a little the rust is wiped away and you no longer hear noise. Even if the brake linings are OK, there are other metal/metal squeaky contact areas that could squeek.
It would be good to take a look inside the brake drums. If the noise is caused by minor rust from humidity I wouldn’t worry about it. If you only use the vehicle once a month be aware that your brakes may not work great at first.
It usually happens after I’ve moved a few feet and my foot is off the brake (but hovering just above in case I need to stop suddenly for passersby, cars or the horrible sound).
I honestly never thought about it being a brake issue since I don’t notice any deceleration (like the brakes engaging) when it happens. My main concern was that it might be transmission related.
I drive it about twice a week. Mainly only on the weekends to and from Home Depot and Menard’s.
I’ve had the ABS thing kick in once. Literally shook rust and dirt off the truck. It was not pleasant, and not the issue I am experiencing.
I haven’t played around with the sound too much. I’m too worried about ruining something or making it worse or making my neighbors angry with the noise.
So it’s been awhile, but I was finally able to catch the issue on video.
It’s not going to win any Oscar’s, but the sound is definitely audible.
I only hear this sound when I’m in reverse. And it doesn’t happen every time, but it did happen this morning in a parking lot and I startled a couple of old ladies.
Is 4-wheel trying to engage? Try putting it in 4-wheel, driving forward a few feet to engage it, then seeing if you can repeat the sound. Long shot and it wouldn’t even make sense, but lets rule it out.
It’s sounds, to me, like something spinning.
Flywheel hitting a cover/guard? Starter reengaging for some odd reason? What’s bothering me is that after you stop rolling it keeps going. Just for shits and giggles, you could start the car, pull the fuse for the starter, then try to replicate it. Again, long shot, but it’s just one more thing to rule out easily.
It seems to be a frequency like engine speed and not anything to do with the drivetrain after the transmission. The “detail” of the sound makes me think something is rubbing like the ring gear or a part that’s external to the engine. Do you have someone to stand outside and try to localize the sound? Does it always happen when you move in reverse?
I’m thinking that something about the engine torque reaction in reverse causes something to rub. Like an engine pulley or maybe the starter is loose on the engine block? Do you feel any “clunks” when you put it into gear or accelerate - like a broken engine mount.?
I think if it was the transmission it would be dead by now!
I actually started to ask about clunks and engine mounts as well, but for the moment, I’m running with some kind of starter problem. It’s an easy one to dismiss (by pulling the fuse).
Then I’d go with the flywheel rubbing against something, which could be a broken engine mount or any other number of things.
A friend with a bright flashlight and good ear would be helpful. Even setting your phone under the truck and watching the video might locate a rattling guard or shield. I’d concentrate on the area behind the flywheel. I let my dad listen to it, his first comment was ‘starter’s stuck’, but when I explained when it was happening it didn’t make sense, however, it still means, to him at least, that it’s a noise from the flywheel.
Has your vehicle ever had the engine or transmission removed? I once had a 1970’s Chevy pickup that started having some strange sounds and I discovered that the lower transmission bellhousing bolts had backed out, leaving a 1/4" gap between the bellhousing and engine at the oil pan area!! I tightened everything up, the gap closed, and I drove it for several more years.
That would be a pretty big honkin’ fuse. The stater motor draws, what 300-500 amps? I don’t think I’ve ever seen a fuse on the starter.
My vote goes to something loose (a starter bolt, bellhousing bolt, maybe even a flexplate bolt) or a bent torque converter access cover. At first, I thought a bad torque converter, but a bad torque converter would be more consistent and would have other symptoms as
well (slipping badly).
When you first start the car in in fast idle most so more sensitive to torquing. Could be a worn moor mount allowing something to rub under the hood or possible even in the drive train.
I had an old 81 Chevy pickup that made a very similar sound. In my case, the was the park pawl was not releasing when I shifted from park to reverse and drive. It would finally release after 3 to 6 tries of shifting from park to a gear. To avoid the problem I would leave the truck in neutral when parked. Took a buddy at a transmission shop $35 and 15 minutes to fix the problem.
That sounds exactly like the cooling fan hitting the shroud.
Open the hood and look at the radiator fan. Are the tips of the blades chewed up.?
If the are you have a motor mount problem. Either the front two or the rear trans mount.
Why doesn’t it happen all the time ? well It could be both a brake problem and a mount problem. The brake problem may occur sometimes… the pads jam on and then its hard to push in reverse… they come off when you go forward. The bad mounts could be for the engine or for the transmission, but either way its causing something to rub badly.
Or it could be a problem with the mechanism (pawl) that clicks in with “P” to lock the vehicle at one spot, its half clicking in with R problematically.
I need to wait until someone is available to help out to check most of these ideas.
In the meantime, I will check to make sure the motor mounts and transmission mounts are tight, as well as the bell housing.
I had a battery issue earlier this year that I thought might be a starter issue. So I pulled it and had it checked at Advanced Auto Parts. It tested fine, but I’ll try pulling the starter fuse/relay after the truck is running and backing out.
Some of you may think that I didn’t tighten the bolts on the starter enough after I pulled it. But this problem has been happening since before I pulled the starter. This issue was just farther down in priority since I can easily fix it by putting the trans in park and it drives fine otherwise.
If it is a starter/flywheel issue I would think that you could see the wear on the flywheel or starter teeth.
So reverse (noise) to park and back to reverse (no noise) seems to be what is happening.
What happens if you go reverse (noise) to drive and then back to reverse? Going from reverse to drive will tourque the engine and transmission in different directions, which might indicate a motor mount problem.
