So I'm about to send this car with my son up to the NOVA area where he's moving in a couple weeks. Got the brake booster recall dealt with, got his Android stereo about working (thread coming soon on that adventure), now got another problem.

When driving at about 40-50 mph, up a slight hill, give a little acceleration, I get a raspy buzzing vibration from the back. As soon as I let off the pedal it goes away. It is very intermittent and does not happen every time.

It almost sounds like you're driving over the indentations they put on the edge line to warn you that you're running off the road. Or a car that has had stereo upgrades, too much bass, and no Dynamat, and the trunk lid is rattling.

I lifted the back, got underneath, and nothing looks out of place. CV joints intact, wheel bearings feel good, can't see anything suspicious.

Any ideas?

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech