Daniel DRG

Hello guys!

So.. i got a 520d with N47d20c / 177hp with the following problem.

When i accelerate, it makes a strange noise in all gears, except for the 5th one, where everything is fine as it should, without any abnormal noise.

Engine noise is fine on acceleration and that particulary noise on acceleration seems for me that its coming from around the gearbox, not from the back or front of the car.

What could be the problem? The gearbox? Or anything else?

Thanks!

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CCC123

I had two Prius that made a sound on acceleration but not when at an idle or crusing speed until pushed… it was the catalytic converter. I’m NOT saying that is your sound problem, but if your catalytic converters are getting clogged, then what happens is they won’t make a sound until you’re trying to get more air through them.

They can let a certain amount through at idle and cruising speed without any problems… then when you accelerate it makes a crispy crackling sound because the air is getting out elsewhere. On my Prius the sound only happened when accelerating, then, subsequently, when cruising at 60MPH, it would only start again when I would give it gas to go to 65MPH. A new catalytic converter eliminated the sound immediately.

The catalytic converter can get clogged simply from too much oil being added to the engine. Or, if the engine isn’t burning cleanly, then burnt oil or burnt anything will simply begin to clog the catalytic converter’s mesh. It’s a mesh of metal and the carbon can buildup like a dirty pan. I’m NOT an expert. Read some articles.

if it’s your gearbox, I admit I don’t have time to search the part number and I don’t know if it is a manual or automatic… but if it is your gearbox then you might be in the wise choice to not keep the car. But obviously if you’re able to keep the car regardless of expenses then it’s always good to get a rebuilt, or rebuild it yourself, transmission! If you have the money or experience there’s never anything wrong with a new part unless you don’t install it right or if it was cheaply made! But if money is a realistic thing, then sometimes we have to let go of what we have.

overall, I guess it could easily be the catalytic converter.