Noises

[aziego]

I have my 2005 M3 for a couple of weeks now and put a few hundred miles on it. It has 128K so I know there will be some things I would need to fix. Driving around there are a couple of noise that I want feedback on.

First is what I believe to be from the differential. I hear it when I am in the parking lot, turning the car I hear a loudish groan. Not all the time and one time it almost sounded like a thump. I am assuming it is from the diff locking up but given my inexperience, I figure I should ask.

Second is a ticking/clicking sound that seems to be right under the cup holder area. The frequency goes up and down based on how fast the engine is turning. Again, not always there. It can be silent and then when I hit a bump in the road the noise will appear. I can only think of the Guibo or center support bearing. Both are on order, and I plan to change asap. Can it be anything else? When I shift to higher gear, the frequency lowers this makes me wonder if it really is the driveshaft. Since driveshaft rpm should not be impacted by a gear change.

[mstalhamer]

For the differential I would definitely recommend changing the oil. In fact probably a good idea to refresh all fluids. Something I typically do regardless when I get a used car. Change Engine oil, transmission oil, rear diff, coolant etc..... I even would recommend the power steering fluid, mine was disgusting with 40K miles only but probably never touched since factory filled in 2006

[sapote]

Second is a ticking/clicking sound that seems to be right under the cup holder area. The frequency goes up and down based on how fast the engine is turning.

I would say the noise going fast and slow depending on the car speed and not engine rpm (in neutral?)

Re the Diff: take a video of the diff rear end reference to floor or the stabilizer bar with camera on ground during moving forward in 1st and reverse. This shows the condition of the diff mounts. Other than this, the noise is normal for old clutch pack that slips during take off and chattering in a turn. No harm.

[aziego]

For the differential I would definitely recommend changing the oil. In fact probably a good idea to refresh all fluids. Something I typically do regardless when I get a used car. Change Engine oil, transmission oil, rear diff, coolant etc..... I even would recommend the power steering fluid, mine was disgusting with 40K miles only but probably never touched since factory filled in 2006

Agreed, I will be doing a fluid refresh. Also plan to get the oil analyzed to see if rod bearings needed. I don’t have maintenance records but the autocheck report does show a couple of engine and transmission maintenance work done.