hi all,im new on here so be gentle if i get anything wrong,

i have an A4 tdi 2.0 auto cvt 2006,i have a horrible grinding noise which is very like brakes grinding when metal to metal but its not the brakes just sounds the same

when its there it only goes on acceleration,and is there when i decelerate its there in nuetral its there in park,its there in reverse but not when i accelerate,and it suddely dissapears aswell

when its there the engine noise seems noisier and there is vibraton through the steering wheel and the pedals.

it had a box fitted at 41k bt audi under warranty and had 70 on the clock now so not even due its 1st gearbox oil change yet,but its 2 and a half yrs ago so out of warranty for that.

any help i appreciate