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.

1.There are plastic bushings in the shifter linkages that wear out and need to be
replaced.Here's the Wicki for R+R:http://www.peachparts.com/Wikka/W124ShiftBushings
1a What shape are your motor mounts in? What shape is your Transmission
Mount in ? 'Things "Bumping Around" down there can have weird effects.
2.Always solve "Power Making" problems with the engine before you try to adjust the "Bowden" shifter cable ( or the Vacuum Modulator)
3.Accelerator control Linkages and Rods must be adjusted to Specs BEFORE
any Tranny adjustments.

This is a great thread on Tranny Adjustments:It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...

AND STEVEBFL's :http://www.peachparts.com/Wikka/TransVacTune

This is the Main Wicki for Mercedes Transmission:Transmission:

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__________________
'84 300SD sold
124.128

Thanks for the links to helpful information. I noticed that the shifting gets smoother and it shifts at the correct times as the car warms up. It seems that the first and third gear are the gears that shift at high RPM's (3K).

Can this be a vacuum problem?

Vacuum problems are usually symptomatically portrayed as "Whiplash" type
shifting (In all gears) [in other words a Vacuum problem would affect ALL GEARS].If you disconnect the Vacuum Line from the Modulator to demonstrate
you'll get Very harsh shifts.
The Bowden cable (From Transmission to the Accelerator control linkage) sets
shift point(s).

I believe you need to adjust:
1.Accelerator control linkages.
2.Bowden cable.

The "problem solving" by warmer Tranny fluid temperatures leads me to:
How old is your Transmission Fluid?
(I'd [second] change out the fluid and filter with Redline Synthetic ATF)

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__________________
'84 300SD sold
124.128