Piston Slap: NVH Nightmares No More? (Part II)

Sajeev Mehta
by Sajeev Mehta
piston slap nvh nightmares no more part ii

Doug updates us:

Hello, just an update on this problem: an indy shop I had used before on another Mercedes put my 2007 S550 on a lift and diagnosed it with a failed transmission mount. Just a little $60 part at the tail end/output end of the transmission.

Because it had failed, the transmission was essentially resting on the frame crossmember, pretty much directly beneath the center console/armrest where I felt the vibration so acutely. I was skeptical it could be that simple/cheap, but sure enough it eliminated the problem! It’s super smooth and silent now. The other likely culprits, the flex discs at each end of the driveshaft and the center carrier bearing for the two-piece drive shaft, all look new and can’t be original. They must have been replaced by the first owner.

Sajeev concludes:

Isn’t it nice when you have a shop that truly understands your brand?

Judging by the condition of the transmission mount (metal transmission so close to the metal body), this one musta been a breeze to diagnose when hoisted upon a lift. There’s no replacement for a visual inspection from someone who knows what the heck they’re doing. So much for my idea about using a Pico NVH listener — that’s total overkill.

Thank goodness for quick and easy fixes. Well, easy by fully-depreciated German luxury flagship standards!

[Image: Shutterstock user pdsci]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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  • Dukeisduke Dukeisduke on Aug 25, 2017

    I'm glad to hear it was resolved, and so cheaply. Was that an M-B part, or aftermarket?

  • Jalop1991 Jalop1991 on Aug 25, 2017

    I'm surprised the $60 part didn't require $400 of labor and M-B proprietary software to match it up to the body computer.

  • Importamation Importamation on Aug 25, 2017

    Thanks for the shout out Sajeev! Doug here. It's still going strong, turned 199,500 tonight. The $60 part was genuine MB as was a $400 lower control arm they showed me was about to have a ball joint come completely apart. I knew I could find the control arm for less than that but the car was there on the lift, I was there, the parts were there, and I had the time to wait, so I just told them to do it. That eliminated an on and off clunk from the front end I had ignored (apparently not a good idea). My youngest has his permit now and wants it, kinda to my surprise, but OK. I'm looking for something else now for myself.

  • Jeff Semenak Jeff Semenak on Aug 27, 2017

    I had a buzzing noise at, and just off of idle caused by a loose heat shield for the Catalytic converter.

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