Audi A4 (auto) 2.0TDI 2008 scraping and grinding when coasting

Maintenance/Repairs
1

Recently had pads and disks changed (all around), new fly-wheel and drive shaft (both sides). Car has awful scraping sound when coasting (same in neutral). When you accelerate it goes, but moment you take your foot off the gas, problem starts. Garage checked all the pads and disks, said fine. Pointed to a gearbox problem, but not convinced as still scrapes dropping car into neutral. Could it be poorly fitted flywheel? Anyone had similar issues. Any help appreciated :pray:

2

Sounds like a heat shield is coming in contact with a driveshaft when the engine rocks a bit on deceleration. Take it back and have the shop check again. I think they just missed it.

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3

Scraping sounds are very often problems with the brakes, so it made sense to start there. Flywheel as the cause seems unlikely, but I guess anything is possible. Before doing anything with the transmission/flywheel, suggest to have the shop put the vehicle on their lift and run it in gear, then shift to neutral. Maybe they’ll spot something from the underside view. If not, and thsi were my car, I’d completely disassemble and probably replace all the brake parts again, before embarking on transmission work.

fyi, there’s a slight possibility of an interference between the the starter and flywheel.

When coasting in neutral and you hear the noise, does pressing on the clutch pedal have any effect on the sound?

4

check that the baking plate is not hitting the rotor. sometimes they get bent and just touch the rotor and make a squeaking sound.

5

The title of the thread says “auto”, so no clutch pedal.

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6

Why did you replace flywheel? Audi dual mass stuff, with diesel? Or not? And car was quiet before work? Trans comes out to do job. And shop is leaning towards trans issues? Seems they might have a good idea. Since they did work.

7

My thought was a heat shield problem; especially since the exhaust has been tampered with.

You might try wrapping an old towel around the end of an exhaust pipe and whacking it with a mallet or even a balled up fist. If you hear a rattle then it’s the heat shield.

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