I have a lead for a used transmission with a lot less miles than my car has. I have a quick lift to get my car off the ground safely and this is not my primary car so I am not super rushed to get it done in a day so I plan to do this myself. What tips and advice before I start down this road?

 

Dropping a trans isn't a big deal at all and can be done in a day.

Make sure you replace the rear main seal while you're there.

 

That’s a good tip. I’ll remember that.
Ive installed a trans once before in a TR6 Triumoh so hopefully it’s comparable.
What about U joints?

 

Flex discs, not u-joints. There is also a bearing and carrier in the center of the driveshaft so now would be a good time to replace the bearing and carrier. Not very expensive as long as you are already in there.

Follow this link and read up on flex disc replacement. Good tips in there that you will need to perform anyway.

https://www.pelicanparts.com/techart...Index-W210.htm

Assuming it is your E320 don't forget to disconnect the battery ground cable at the connection in front of the rear seat.

 

I found a shop that specializes in Mercedes transmission rebuilding and supplies shops all over so cal. They cut me a break and I installed a rebuilt with new trans mount and other stuff. Runs great now.