Originally Posted by MANDD
For Item 2, I have done quite a lot of these. This is very common on the E90, the noise is fron the rear differential pinion flange.
The fix is to remove the flange, clean splines and then apply loctite 290 to the splines. Grease the rear cup, replace the shaft seal and lock plate.
man you guys are great.. thanks! I can't really DIY this.. so my follow up questions are:
1) Is this something that I HAVE TO get fixed or is it strictly an annoyance
2) Where can I get something like this fixed
3) How much do you think it is gonna cost me?