Grinding/crackling sound when accelerating
 

Hello,

I've been doing some searching and can't quite find a description that I'm sure matches what I've been experiencing.

My car has been driven only periodically, for a total of less than 500 miles over the course of a year. All seems normal but now I'm noticing a crackling/grinding sound coming from somewhere when I accelerate soon after shifting up. I usually hear it on gears 2-4. I think I tend to notice it most when I'm cruising for a while on gear 4. There's a pretty loud crackling or grinding like noise that lasts for a few seconds. I don't notice any vibration or performance issues, just this noise.

It's an early 2005 A4 1.8t 6 spd manual.

Since I've been gone, my car has been driven less than 500 miles by a friend, just to keep the fluids circulating. I know how they drive and they usually shift smoothly so I don't think they could have messed up the clutch or gears. I did have a different friend drive me home a few days ago when I was a little tired. He mentioned he stalled a couple times (I was asleep so don't remember). It was after that that I starting hearing this noise.

Does anyone have any ideas of what this could be? I've read about something with synchro's making this noise and I wanna say that is what is causing my noise but again I'm not experiencing any vibration or performance issues. Thanks.

Could you also describe that noise as a thumping noise? Mine also does this and it seems its more of by the tires. No idea what it could be.

I wouldn't describe my sound as a thumping sound. Just a grinding/rattling sound.

Actually I went to get an oil change and had the mechanic check out the sound. He couldn't get into much detail but it was his opinion that my noise was not coming from the transmission or the motor mounts. He found that my exhaust is actually quite loose and on first glance, he thinks a weld broke or something and the noise is the exhaust rattling around when I accelerate.

So I'm gonna get the noise investigated more fully but I'm hoping it's just a loose exhaust that can hopefully be easily fixed with a new weld.

My mechanic already checked out my motor mounts. He saw that the engine is not jolting as it would if the motor mounts were bad.

In your case, does the noise seem to be coming from the engine and does the engine seem to shift and thump as if it's hitting a wall every time you accelerate? That would probably be a motor mount. Hopefully others can chime in.