Sounds like you aquired a 240d with the usual smaller maintenance items ignored.

Try to establish where the two quarts leaked out of the tranny. The cooling lines are always a good place to start. Although having to add a little transmission fluid from time to time is not the end of the world.

With a little good fortune checking the glow plugs for good function. Combined with a valve adjustment as already mentioned may make a world of difference.

As with almost all the used two forties I have seen. Check that the linkage to the pump has full travel before complaining that people on bicycles are passing you.