Need help with loud whine noise
Thread Starter
Newbie
Joined: Feb 2016
Posts: 5
Likes: 1
2008 GL450
Need help with loud whine noise
Hi, I need help with a loud whine noise on a 2008 GL450. 40k+ miles.
Back story, I stepped on it to make it through a yellow light, after the intersection I stepped off the throttle and the engine died. All the warning lights came on and 0rpm dead. I pulled over, restarted and kept going. Shortly after I heard the whine noise. I'm not sure exactly when it started, possibly right after that restart?
The noise seems to be coming from the lower engine/transmission. More like right over the torque converter area. The car starts, drives and shifts well. No codes in engine or transmission. I have access to a snap on ultra scanner.
It almost sounds like the power steering whine, but steering is fine and noise doesn't change with steering. Noise is RPM dependent. Goes faster with increase in RPMs. There is also a loud ticking noise at idle, that really can't be heard at higher RPMs. I took off the serpentine belt and the noise is the same, so it's none of the pulleys or bearings associated with the serpentine belt driven items.
I am a bit overdue for the 40k fluid change in transmission.
Any suggestions to try find the problem...
youtube video of noise:
Thanks.
Back story, I stepped on it to make it through a yellow light, after the intersection I stepped off the throttle and the engine died. All the warning lights came on and 0rpm dead. I pulled over, restarted and kept going. Shortly after I heard the whine noise. I'm not sure exactly when it started, possibly right after that restart?
The noise seems to be coming from the lower engine/transmission. More like right over the torque converter area. The car starts, drives and shifts well. No codes in engine or transmission. I have access to a snap on ultra scanner.
It almost sounds like the power steering whine, but steering is fine and noise doesn't change with steering. Noise is RPM dependent. Goes faster with increase in RPMs. There is also a loud ticking noise at idle, that really can't be heard at higher RPMs. I took off the serpentine belt and the noise is the same, so it's none of the pulleys or bearings associated with the serpentine belt driven items.
I am a bit overdue for the 40k fluid change in transmission.
Any suggestions to try find the problem...
youtube video of noise:
Thanks.
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Joined: Jun 2006
Posts: 1,140
Likes: 118
From: Nova Scotia, Canada
2023 GLK250, 1987 560SL
It could be your alternator. They can get pretty noisy.
I don't think it's your power steering. Hydraulic pumps whine in a different way.
Open your hood and get a dB app for your phone and see if you can pinpoint the location.
I don't think it's your power steering. Hydraulic pumps whine in a different way.
Open your hood and get a dB app for your phone and see if you can pinpoint the location.
MBWorld Fanatic!
Joined: Dec 2004
Posts: 4,268
Likes: 253
If you are sure it is not one of your belt driven accessories .... It could be your output shaft bearing or tranny input shaft bearing... It certainly does sound like a bearing.
On a second thought, it could be also a timing chain tensioner. Especially with the ticking noise you describe.
On a second thought, it could be also a timing chain tensioner. Especially with the ticking noise you describe.
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Thread Starter
Newbie
Joined: Feb 2016
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2008 GL450
I didn't use the DB app, might try it on monday. But I was listening to it again today. It seems the noise comes from the engine/tranny connecting area.
Timing chain runs in the front?
The ticking noise is hard to pinpoint. But I think it's coming from the same area which is throwing things off if it's just a bearing??
I was reading up on the internal pumps of the 722.9 transmission failing, but can't really find common signs of failing pumps. I have more reading and searching to do...
Timing chain runs in the front?
The ticking noise is hard to pinpoint. But I think it's coming from the same area which is throwing things off if it's just a bearing??
I was reading up on the internal pumps of the 722.9 transmission failing, but can't really find common signs of failing pumps. I have more reading and searching to do...
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Newbie
Joined: Oct 2014
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2005 clk 500 convertible
Power steering pump
May not be it but my nose went away completely when I had exchanged the power steering pump. It was leaking when I bought it and they tried to hide it. Once replaced the sound was gone for good. I have a 2008 and looks like it's a very common issue. Sucks that the part is 500 bucks.
Thread Starter
Newbie
Joined: Feb 2016
Posts: 5
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2008 GL450
Update:
The noise was caused by a failed bearing in the transmission oil pump. New oil pump has needle bearings instead of the friction bearing.
Finally put it all together and all is well.
Tips for others (I'm not a mechanic, so do your own research)
youtube has an excellent series on the 722.9 transmission assembly and disassembly. They include all torque values for the bolts. You'll need the new oil pump (best price is eeuroparts $370). Possibly new torque converter ( 300$ refurbished from torqueconverter1.com with 1 year warrenty. I was able to pry, file and sand away the seized bearing and reuse my converter. I bought shell oil ATF 134.
Before opening the bellhousing, you have to take out the valve body and take out the oil feed tube to the B3 clutch. ( I broke mine because I didn't think I had to take it out) You'll need all new bolts for the stator to bell housing. They are single use aluminum bolts. Also new bolts for valve body. New oil filter, gasket for oil pan, new bolts and oil.
To take the transmission out, you'll have to take out exhaust and all driveshafts. Leave transfer case mounted to transmission.
Transmission doesn't require any special tools for disassembly. a couple different torx sockets and torque wrench.
Amazon has miteyvac adapter for the transmission to pump in oil. Much cheaper than the other brand mention in the oil change pdf found on this site.
The noise was caused by a failed bearing in the transmission oil pump. New oil pump has needle bearings instead of the friction bearing.
Finally put it all together and all is well.
Tips for others (I'm not a mechanic, so do your own research)
youtube has an excellent series on the 722.9 transmission assembly and disassembly. They include all torque values for the bolts. You'll need the new oil pump (best price is eeuroparts $370). Possibly new torque converter ( 300$ refurbished from torqueconverter1.com with 1 year warrenty. I was able to pry, file and sand away the seized bearing and reuse my converter. I bought shell oil ATF 134.
Before opening the bellhousing, you have to take out the valve body and take out the oil feed tube to the B3 clutch. ( I broke mine because I didn't think I had to take it out) You'll need all new bolts for the stator to bell housing. They are single use aluminum bolts. Also new bolts for valve body. New oil filter, gasket for oil pan, new bolts and oil.
To take the transmission out, you'll have to take out exhaust and all driveshafts. Leave transfer case mounted to transmission.
Transmission doesn't require any special tools for disassembly. a couple different torx sockets and torque wrench.
Amazon has miteyvac adapter for the transmission to pump in oil. Much cheaper than the other brand mention in the oil change pdf found on this site.
