marktan

The car has developed a whine over the last year that has become really annoying and I figure it's time to take a serious look into it. I can't tell if it is ABC tandem pump or transmission noise though. It is definitely RPM sensitive and spans the entire range. Volume and pitch increase in a linear fashion as rpm increases all the way to shift point, so I don't think it's the low RPM noise of an accumulator/dampener going bad, but I don't know. Affects all gears although it's most prominent in 1-3 (where higher RPMs can be reached).
No fault codes current or stored on STAR-Xentry diagnostics for either the suspension unit or the transmission unit. I even rodeo'd the car twice and the pressure maintains at or near 190-bar the entire time. So I don't think the pump is "failing" as far as pressure, but that doesn't mean a bearing hasn't gone bad. No issues with settling or ride either. It doesn't make as much noise in PARK, but I think there may be a little chatter from the pump pulley as the rodeo took pressure on and off. The car now has 120k miles on it. Trans and ABC fluid and filter have been changed twice in the last 60k miles I've had it (paranoia more than anything).

I've taken a video of the whine that you can hear over the engine. The end is a downshift into 1st gear to get it to "sing". Has anyone heard this before? Thanks!




Any thoughts?

marktan

Fixed the video privacy so it should play now...sorry!

tusabes

Sing? you barely had the car over 2000rpm

Do you ever take it above 4000rpm??

marktan

Lol. Constantly. Sorry, I was in a resedential area. If you can't hear it, I'll try making another later and posting it too. A friend said it sounded like the supercharger whine from my old C32 ///AMG
It whines less when throttle is applied as opposed to no-load if that makes sense. Makes me think it's a pulley. I've had the belt tensioner and all idler pulleys replaced, so it's not those making the noise.
Thanks again.

Video #2:

Video #3:

wallyp

Belts, pumps, etc. don't know or care whether you are coasting or power-on. Perhaps transmission pump or planetary gearset?

pwrtruck1

My S55 is making a similar noise (it has for almost two years) but perhaps not as noisy. It recently has gotten noisier and more irritating. I originally could feel/hear it most from inside on the drivers side, front floor board better than anywhere else. Are you experiencing that also?

Also, usually higher speeds would drown the sound out more but lately its gotten louder and noticable vibration (almost sounds like exhaust).

marktan

I'm getting frustrated too! I can't tell where it's coming from other than "forward" maybe even "forward left" (from the drivers seat) which is why I was thinking ABC pump. If I accelerate around a corner hard from a stop, it gets particularly loud until it levels out straight (another reason I think it's the ABC rather than transmission...like maybe the pump was straining under heavy load in the turn trying to level the suspension).
I can't, however, get it to make an obvious noise in park or neutral just revving the engine, so that made me think Tranny.
It doesn't seem to affect the drivability of the car...just annoying to listen to.

pwrtruck1

I just read another posting and sound clip that sounds exactly like mine. The owner said he replaced the damper on it and it solved it. I am still looking, I need to be careful on what I spend. I'd like to get rid of the car, but so far haven't been too lucky. It's been a love/hate relationship with this car. Please repost if you solve your noise. I also just had the inner control arm bushings replaced and my ABC warning message is on. Displeased with all that goes wrong with these cars.

marktan

I was under the impression the dampener would create a hollow groan/howl at only lower (1200-1600) rpms. That being said, the dampener is a hell of a lot cheaper than the ABC pump and may be worth a shot. I heard we have 2 or 3 of them under the car. I saw a baseball sized one on the passenger side by the wheel well when I was replacing the rear duovalve last weekend.
May be time to crack out the Xentry-DAS/WIS diagrams.

I just hate to keep throwing unneeded money at this thing.
I just got my wife a GL450 last week because she has been wanting an SUV. I tried trading my S600 (2005 w/ 118k miles) in and they offered a "whopping" $8500 for her.
Claimed there were only 5 in the nation being sold based on the auction data and the two that were over 100k miles were only selling for $5000-$9000 at auction. That's fine. For that lowball offer I'm going to keep her.

So I gave them my 2004 E500 4-Matic w/ 70k miles and got $13,500 in trade with a cracked front bumper (young daughters are always an adventure "Dad, I rear ended someone at a stop light, but I don't think it was my fault...the light turned green but they didn't move").