Help with CL203 Transmission

[Picko]

Hello all.
I'm having issues with my CL203 220cdi C class (https://commons.wikimedia.org/wiki/File:Mercedes_C_220_CDI_Sportcoupé_(CL203)_front_20100704.jpg). It is a diesel with an automatic transmission. When it is cold outside, and the engine hasn't warmed up, the car feels like it struggles to change low gears, and will lurch randomly when going below 30mph. The revs will also 'bounce' up and down at any constant speed below 30 mph. The car seems to work fine once the engine temperature goes up.
Has anyone experienced anything like this?
The car has 100k miles on it and isn't worth very much, so if anyone knows if it is something I can service on my own (my experience is limited but willing to put the time in to learn), that info would be really appreciated.
Thank you all.

 

[pgh13]

Hi, and welcome to the group.
First questions are going to be mileage (which you've given), which transmission is it (5 speed, 6 speed etc) and do you know if/when it was last serviced

 

[Picko]

It's a 5 speed, not been serviced in 3 years (have one bookes though)

 

[pgh13]

The conductor plate thread at the top of this section is an excellent how-to guide.

 

[Steve@Avantgarde]

This fault is caused by the lock up clutch control valve.

It will require the valve body taking out, stripping down and replacing the valve. You can buy it from Mercedes for about £100. If you have an Independent do the job it will cost you around £400 which will include changing the oil and filter in the transmission.

Its not a difficult job, you just need to know what you are doing.

 

[Picko]

Update: I paid for diagnostics and they reckon it's a fault with the torque converter lockup clutch. I didn't want to pay for the fix as the car is almost worthless, and they recommended two tubes of Dr Tranny's shudder fix. Will update if it works or not.

 

[Steve@Avantgarde]

I gave you the fix and the crappy shudder sauce will just make things worse.

I've replaced hundreds of the TC lock up valves for this very fault.