This is my first Mercedes, and my first diesel at that. It is in fairly good condition and I'd like to replace and repair what I can on it. I'm not very savvy with car engines. It has 229,109 miles on it, and the odometer quit working in the last 12 months or so, but he claims the engine has been rebuilt with around 40k miles on it. Any help or advice would be greatly appreciated!

It's a smooth ride and I love it already! Built like a tank! It just needs a little TLC

 

By the way, does anyone know the approx. speeds at which it is supposed to shift? I'm a little concerned about mine, but it may be nothing. I haven't quite figured out all the noises yet (which are normal and which aren't).
It's a 4-speed automatic.