To add to what Len said, MB has now decided the trans does not have a lifetime fill and does require service. I think the recommendation now is to change fluid and filter every 40-60k?
You do need to use only MB fluid, either for the 722.6 (your trans) or for the newer 722.9 G-Tronic trans whose fluid is backward compatible with your unit and is also a few $ cheaper than the original fluid.
The dip sitck is a factory "tool"; you'll need to get a new red lock too or the cap WILL vibrate off. Ask how I know....
