Hi guys, I took out my TCU to get it tuned. Noticed oil on my hands and saw that there was oil around my TCU connectors/ connector wires. I put the TCU on its side and let the oil drip out. Attached are the pics.

1- What kind of oil is it?
2- Is this normal? Whats the problem? Where should I start looking?
3- What to fix? How much labor / cost?

2003 SL55, TCU is located on the right side panel of the passenger footwell.

Search the forum. This is a known problem. Consider yourself lucky that you caught it in time.

1- What kind of oil is it? Transmission oil
2- Is this normal? Whats the problem? Where should I start looking? Common problem, wire harness connector on the transmission conductor plate will need to be replaced.
3- What to fix? How much labor / cost? 40 dollar part about 10 mins to replace

open the tcu and clean it with electrical circuit cleaner

The O rings degraded on the control cable plug on the transmission. The pressurized ATF fluid is being force up the inside of the cable jacket into the car. The same transmission type was used in many Mercedes and Chrysler vehicles and all dealers know about it. Google "NAG plug". The plug costs under $20. The O ring material has changed multiple times over the years. I'll bet the new O rings won't last any longer than the old.

It is a messy job and takes way more than 10 minutes. Do it with a cold engine and the car jacked up to keep much of the ATF fluid away from the connector. Even so orange ATF is going to stream out. Be patient and meticulous. Be sure to get the two old O rings out. Be sure to index the new connector properly and don't forcibly twist it. DO NOT over tighten the plug's retainment screw. If you do prepare to spend big bucks.

Thanks guys, will look into it when i get my tcu back.