i found alot of sludge and the oil was thick black when i recently changed it.alot of sludge meaning when you touch the pan,it felt like a cushion as it was full of it.i thought changing oil,filter and cleaning it would make it better but i dont see much of a difference.it was done professionally.does anyone know whats wrong?
its a audi a6 99 2.8 quattro
its a tiptronic

thanks
kushan

 

you may need to do it again, and again after another 500-1000 miles; changing the filter also every time.
If it was that gunked up, then just one time won't make too much a difference as the buildup in the torque converter doesn't get cleared up instantly. You only drain what's in the pan pretty much.