A droning sound has appeared starting at around 60km/h in top, it reduces as the car passes 80km/h. It started as a patter 2x a second and within 20km has changed to a continuous drone. Letting the freewheel kick in or pressing the clutch at 60km/h makes the noise go away. Rev the engine up to a similar engine speed with the clutch disengaged and the sound is does not appear. I checked the drive shafts which both have a small amount of vertical play at both ends which I presume is not as they should be. However, driving round a car park full lock in both directions does not produce any drive shaft noise. I have not checked the gearbox oil since buying the car, I will try and do this tomorrow. I plan to swap the drive shaft oil seals at the gearbox end and then replace the oil. There seems to be oil covering the drivers side drive shaft boot at the gearbox end. The inner drive shaft joints were greased shortly after buying the car. If it was crankshaft and bearings why does the droning sound appear at 60km/h over halfway up the rev range? Why is all smooth at lower engine speeds? I have fitted winter tyres on the car this weekend, all the wheel nuts are tight. I am not sure if this droning is the engine, crank/bearings or gearbox/final drive or even drive shafts. Or if it is normal and acceptable. My main concern is that the noise has appeared in the last couple of days. Any suggestions for possible causes and/or diagnosing the problem further?