Buzzing sound when in gear
 

1994 c280 75k miles.

Sometimes when I put my car in gear it will make a humming noise. It won't do this when in N or P, but will in all other gears. It's almost like a humming/buzzing sound. It goes away in a couple of minutes once the car is warmed up. It has me concerned though because I know it's not going to go away on it's own. Last transmission/converter change was 10k ago.

Does anybody have any ideas what this may be?

Thanks

Engine mounts????

If it was the mounts, why would the noise go away after a little bit? Thanks.

mine does the same- i was advised to try turning the steering to the stops with it in gear - does the buzzing get worse? if it does - definately the engine mounts (the steering on full lock gives a bit more work for the engine). or try it in neutral / park - does the buzzing start?

i think it is because the oil in the gearbox is cold, and therefore take a bit more work to turn.

I'll try turning it tomorrow and see what happens. The noise goes away in Neutral and Park.

Could be the shifter bushings wearing out if they are same/similar to my 300D. At certain rpms mine would buzz/vibrate. Maybe different gear positions load them up so they are quiet/noisy. Don't know why it would change when hot, though.