Scraping/ rusty sound on accelerating

[Lcm]

Hi
Please forgive any ignorance, I'm new to Mercedes and not exactly full of knowledge on cars anyway.
Recently purchased a little 06 plate B Class, 1.7 petrol. I've noticed that when accelerating, especially at slower speeds, there is a scraping sound, I'd describe it as a 'rusty' sound. The sound goes away once speed is hit for that gear? I also noticed when sitting idle and then putting in gear or taking out of gear, there is a small 'clunk' sound. Don't know if the two are connected. The dash flashed up with Battery alternator visit workshop aswell.
The previous owner said the alternator was replaced about 4 years ago.
Any thoughts greatly appreciated.

 

[Sweetooth]

Hi and welcome I see you've posted on the engine forum.I'm sure someone will be able to help you out.

 

[BenA]

Doesn't sound like it has anything to do with the alternator...if it's an auto might need the auto gearbox fluid changing they are often supposedly "sealed for life" but after 14 years, the oil will hav degraded. How many miles has it done, and do you know if the transmission fluid has been changed?

 

[BenA]

Ah - I see from your post on the engine forum, it's a manual. so ignore my above post!