Everything was fine... until this noise came up!!! Please help!

[ACS S3 Sport]

I just changed the car engine oil, transmission oil and diff oil on Friday.... the car ran SOOOOO smooth (still very smooth at the moment).... but somehow eva and me heard a strange noise while I was turning left ( on Saturday afternoon)... it sounded like something was scrapping at the rear end of my car (never experienced that before)...

Then it was gone, so I didn't pay attention to it anymore until I reversed my car from eva's drive way about 5 hours later, the noise came up again.... and I felt like the rear wheels spun for a second or so when the noise was there... drove 20 mins back to my place, the car performed smoothly until I did the reverse again on my drive way.... same feeling as before with the same noise....

It is from the rear end of my car though... and I am sure nothing is loss because I asked BMW dealer to tighten everything on Friday!

Is it possbile to be the diff locking up due to the new diff oil? ( I don't know what diff oil they used though... probably the standard one... but they might have put in the racing diff oil for me... just like the transmission oil)

Also I checked my engine oil level... it is about 2mm above the 2nd mark of the dipstick.... will this affect the car's operation at all?

I hate going into the dealership again.... but I think it is necessary to go in once again.... does anyone know what is wrong with it????

cheers and thanks for any help,

richie

[Raysclubsport]

Ritchie,
they must have put the wrong oil in the diff. if they put transmission oil in the diff,then you really will have noises,especially during slow turns. Find out exactly what they put in there, if not sure. just get the right stuff and have it changed again.

[ACS S3 Sport]

Thanks Ray!!!

Other than that slow left turn I made, there was no noise for any other turns though... or this noise will come out just by chance or constantly?

Will this wrong oil incident (assume they put in the wrong oil) kill my diff?? Can I drive the car or better leave it in the garage until monday morning when I put the car back to the dealership..

thanks for your help Ray!

richie

[Raysclubsport]

Ritchie,it should not "kill" your diff over a short period of time, but it all depends on what got into your diff can deteriorate the clutch discs in the differential assembly.I am sure once you get the correct fluid in the diff,you'll be fine. I have the list of proper fluids at work ,i just don't have access to them now,sorry.
about driving the car, just drive to where ever necessary.should not hurt just for the weekend.

[M2DA3RD]

Ritchie, look under your car, you may have picked up some trash or something else dragging on the road. Sometimes the simple solutions are the best. I doubt that the wrong oil in your diff would cause this much noise so soon. Since you are going to change the oil anyway, go with a good synthethic.

[ACS S3 Sport]

Ray and M2DA3RD:

Thanks for all you guys helps!!! I will just take it easy and check out all the possible causes at this stage.... and bring it straight back into dealership on Monday!

cheers,

richie