Humming sound..can't figure it out..audio attached

mal81394 · Post by **mal81394** » 07 Apr 2018, 22:38

Ok great I appreciate you giving updates on this. The weather here has been to bad for me to go out and lay under the car to look at the engine mounts. The car drives so perfect I haven o idea what the source is. I hope the wheel bearings solve it for you...this has to be getting expensive for you. I thought about checking my AWD front diff and rear diff but again haven't had a chance to do that either. Hope to hear from you soon.

mal81394 · Post by **mal81394** » 16 Apr 2018, 14:51

SuperHerman wrote: ↑07 Apr 2018, 21:09 Latest update. My guys pulled the wheel bearings and they were 144k old but felt good. They will be replaced regardless as I bought new ones. I will swap out the left CV as I have a spare with only 75k on it, just to eliminate one other item.

In the process they found metal in the chain drive front differential. Original thought was the final gear was the issue, but when they ripped into that they found it all intact and looking fine. Thought now is the metal was from a seal spring that became dislodged and was chomped up. Parts are on order and will have the front differential resealed and examined. Tranny pan showed now signs of metal out of the norm, just tiny amounts on the magnets and the fluid looked great as it only has 10k max on it.

So once that is done I will report back on whether the new used CV and wheel bearings solve the problem.

SuperHerman, any update yet on this? I am hoping this solved your problem...

Post by **SuperHerman** » 16 Apr 2018, 19:42

Not yet. A small set back. My guys messed up and caused damage to the transmission. Fortunately I had parts from a spare core in my garage and was able to get it to them today. I will update when it is back on the road. This car is taking its toll on me.

Mattbchillin · Post by **Mattbchillin** » 17 Apr 2018, 09:02

Rear differential? This is being done on my 2008 right now with 137K. Mine was most notable on deceleration in the 30 mph range. I thought mine was wheel bearing noise but nope

mal81394 · Post by **mal81394** » 18 Apr 2018, 12:47

Mattbchillin wrote: ↑17 Apr 2018, 09:02 Rear differential? This is being done on my 2008 right now with 137K. Mine was most notable on deceleration in the 30 mph range. I thought mine was wheel bearing noise but nope

hmmm...mine sounds like it is coming from the front. Were you able to hear the audio?

Post by **SuperHerman** » 18 Apr 2018, 14:54

Mal81394 - Have you ever checked your fluid level and condition for the transmission, and differentials? You may be low on oil and driving it may be causing harm. That is the first place where I would look. I looked back through the posts and noticed I did not see any information on fluid level and condition.

Mattbchillin · Post by **Mattbchillin** » 19 Apr 2018, 09:06

Sorry couldn't hear the audio, my sound was coming from rear seat and floor is where I heard it the most. Upon acceleration everything was good, a little noisy. The main noise came on deceleration and coming up on stop signs. I also tried the cornering to see if it was wheel bearing but nothing made a difference.........$1800 later it sounds much better but on a side note they pulled codes and found out the abs wasn't working correctly, another $800 and it seems fine. The repairs are almost half what I paid for the car

Post by **SuperHerman** » 22 Apr 2018, 12:05

Okay - the latest update. Noise is gone. The source was most likely the wheel bearings, don't know which side because both behaved well and turned fine on the bench once removed. They both had 144k on them. I had both replaced. I also learned that the MOOG wheel bearings sourced from Rock Auto are made by SKF.

Here is where things get murky as to the source of the noise.

When pulling the half shaft out on the right side it was discovered a spring in one of the seals came off and got chewed up. My guys then pulled the transmission cone (ext housing). Upon reinstall they did not seat it correctly so the final drive ring gear was destroyed. Big chunk missing. As said in my earlier post I fortunately had a spare. My guys, disregarding my advice, pulled the engine and transmission by dropping it out the bottom. They proceeded to pull the tranny apart and replace the broken final drive ring gear (which basically required the entire transmission to be stripped down). While out I had them replace all the seals in the bevel gear and chain drive unit as it had the broken spring pieces in there. While the engine was out, the turbos were easy to remove so we rebuilt those, the turbo rebuild kit was only $200 for both and they were showing signs of leakage at 144k miles. All said it took an extra two hours to remove, rebuild and install. Everything was bolted back, and the spare left CV I had them use had a boot tear so they put the old one back in after they road tested it. (I think this eliminated the CV as a source of the noise as the original is back on the car and makes no noise).

So the noise was either the wheel bearings or the front differential that had the chewed up spring in it. I would say it was most likely the wheel bearings as the noise was there before work on all the other parts started and I think the earlier work dislodged the seal spring that was chewed up.

What I had done with no effect - new tires, all new engine mounts, left CV axle.

As the transmission damage was their fault, they are not charging me for the extra work. I will pay them something as they did fix the turbos and I feel bad.

To OP, start by checking your diff fluid levels and then focus on the wheel bearings.

mal81394 · Post by **mal81394** » 22 Apr 2018, 20:48

Thanks for that SuperHerman. To address your earlier point...I did just replace the transmission fluid so I know that is fine but I have not checked the differentials I probably should do that. I was thinking this wasn't a wheel bearing noise but it seems in your case that it was which is interesting. I am glad you finally got rid of it though that is great. I guess I will continue to investigate mine and report back. I hate to throw bearings at it without having a pretty good idea they are causing the problem. Mine does seem to go away however when I do a hard turn/pull to the right I believe it is....maybe this is a wheel bearing.

MattbChillin- I think we have different problems. Mine is upon acceleration rather than deceleration.

cutiepiesham · Post by **cutiepiesham** » 03 Jan 2020, 22:10

Well my humming noise was diagnosed today thanks to Pep Boys. It is going to cost me 985.00 to fix. It is the power steering pump. I have another problem. I seen someone else mention it about the turbo leaking. That's happening as well. So that is an added cost.

Just thought I'd share. I've put alot of money into this car. I bought it used and didn't pay quite as much as I'm putting out. I am going to get it fixed but will be waiting awhile.

Humming sound..can't figure it out..audio attached

Re: Humming sound..can't figure it out..audio attached