#Driveline

Doug writes:I have a 2007 Mercedes-Benz S550. I accidentally bought it in 2014 off eBay (long story) for about trade-in ($13,000), with 150,000 miles on the odomater. In a twist of good luck, it turned out to be a one owner car and using CarFax I was able to see and verify that it had been maintained by the selling dealer right up to a few weeks before its eBay appearance. A call to the dealer confirmed the complete service history. Even the brake pads and rotors were new, and it had a newish and very expensive set of Michelins. Almost three years later, it has been very reliable for my teen daughter and has 180,000 miles. It had a few quirks I have fixed myself (clogged charcoal canister, minor trunk leak caused by a missing rubber plug, sticking power driver seat) and only one real repair (dead stereo amp rebuilt by Becker).Now that my daughter is off at college and content with a ZipCar, I am driving it and intend to keep doing so. I have noticed a vibration in the center console area of all places, while driving around town. You feel it through your arm resting on the console lid. It’s a deep vibration, if that makes sense — coming from under the car.You don’t feel it in the seat, nor do you feel it in the steering wheel. You do not feel it at a standstill, just at 20-30 mph. It goes away at higher speeds, and the car is rock solid and smooth as glass at 75 mph. I am stumped as to the cause, and with the age of the car, I don’t want to set a dealership or even an indy shop loose on it without more of an idea of the cause. I was thinking maybe a motor mount, but it seems like I would feel that all the time, and especially at idle, which I don’t. I was wondering about maybe some kind of driveshaft or transmission mount or connection point, but it seems like a fault that would get worse with increasing speed instead of going away. Do you have any ideas?

James writes:

Hi Sajeev,

I’ve got a 2003 Impreza WRX (blob-eye) that’s covered 96,000 km now. I bought it two years ago from the original owner, who seemed to take very good care of the car (every receipt since new). The car has been almost faultless.

About 4,000 km ago, at 92,000 km, the original clutch was clearly on its last legs. Under wide open throttle in 3rd gear, the clutch would slip and struggle to get power down. So off it went to a local WRX specialist to have the clutch replaced with a new kit: new pressure plate, machined flywheel and new Exedy OEM (standard, not heavy duty) replacement clutch.

However, when I got the car back, it felt completely wrong.

Mark writes:

Sajeev–

Here’s a weird one to test your skills of remote diagnosis. Fire up your Magic 8 Ball for this one.

Car: 2012 Mustang V6, manual gearbox, performance package (currently running some crappy General AS Max-03 tires), 33,000 miles. I’m the only owner; special ordered to get it just the way I want. Mods limited to a Shaftmasters one piece drive shaft ( scared into it by a few YouTube videos), a Draw-Tite receiver hitch to pull my one bike motorcycle trailer, and an 87 octane tune uploaded via SCT (on your recommendation). The car will go into a nearby Ford dealer for a look at this issue under warranty this coming Friday, but based on the “quality” of some of the work I’ve had done over the years, I thought it would help to give the techs some clues.

Problem: For the past few days, I’ve heard irregular “bangs” or “clunks” from under the car.