BMW: hi agin 1 other thing i would..., thick oil, gear lube

Question
hi agin 1 other thing i would like to ask is the drive box sounds a bit rough when u turn the rear wheel ,could this be needing toped up with oil or does it usally have to be replaced

Answer
Gary,

 I'm taking it that you are from England/Australia as I'm not sure what a "drive box" is.  I'm guessing you mean Transmission or Differential.  Anyhow, like your engine, these two parts need their oil changed, only less often.  If you have an automatic, it's pretty strait forward, just replace with ATF (automatic trans. fluid).  If you have a manual transmission, you can drain it, but it needs to be refilled through the side of the trans.  A really thick oil (usually called "gear lube") should be used such as Mobil 1 75w-90.  Most people say that Redline MTL is the best oil to run, and makes the transmission shift easier.  
 Then you have the differential, it too needs it's oil changed occasionally.  Like the Manual transmission, it takes a really thick oil (cant remember viscosity), and I'm sure it will help any issues with the car.  As far as the sound you are hearing, it could be many things.  It could be bearings, brake rotors, differential, etc...  So try and narrow down exactly where the noise is coming from.  If it is coming from the Differential, then change the oil, and see if it helps, other wise it could be bearings inside the differential.
 Let me know what you find....
 Josh