SNZ

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.

marc hanna

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.

SNZ

I took off the serpentine belt and the car still makes the same nosie. That would rule out the alternator

marc hanna

Yes, that would. Any luck in pinpointing the location?

islandbeef

marc hanna

Let's sort it before we make catastrophic conclusions

alx

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.

SNZ

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...

supertimo

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.

SNZ

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.

clvincent

thanks posting back and letting us know what it turned out to be

hope it is good from now on

raineycd

Thanks for the info!!! Mine just started the whining and tranny doing odd shifts, etc. Exact same sound, so off to the mechanic I suppose.