Reposting from another thread.... New to the forum here! Been obsessed with DIY maintenance and upgrades on my 08 335xi e90 since I got it a couple years ago. I've been hunting down what is either my front diff going out, a bad wheel bearing or...??? Today I put her up on jacks and pulled the entire front underbody off along with the metal brace/tray. Cleaned everything, inspected for leaks, and anything blatantly wrong. I've got an oil leak coming from somewhere. I recently did my oil filter housing gasket, new valve cover & gasket, had new turbos out in about 5k ago and have been totally anal about fluid changes. Tcase, both diffs, AT fluid/sleeve/filter all in last 4k miles. I was told I had a small leak in my 'bed plate' when my turbos were replaced under the extended warranty. They offered to fix for $6k and I declined as it was way too much and nobody I found online had ever heard of it...no documented bed plate leaks anywhere online for the N54. Now I'm a little panicky as I'm starting to think it may indeed be a bad seal/gasket on the bed plate. Ugh!!! Found a little play in & out in both half shafts but no leaks....CV boots are nice and rubbery/new looking. I pulled the fill plug and decided to drain the oil.... got a little more than a half a quart out....not good. Filled back full. Noise still there. Pronounced when get up to 40+ mph....let off gas and it gets loudest....throttle and it gets quiet....gas again and it quiets down. Either bearing or worst case my front differential gear is worn?? Oh joy!!!