I have a 1990 300D (2.5 TD) with 160K miles and there is a strange noise coming from the gear shifter console when I accelerate. If I have my hand on the gear shifter or move it slightly to the right when in "Drive", then the noise diminishes a bit.

It also seems that this noise started occuring at the same time when the car started to shift roughly as I accelerate. The car goes into second gear once I hit 3,500 RPM and it shifts rough.

Any advice on what these two problems can be? Thanks.