I like to think in terms of what your true goal for the car is. Do you plan on it being your daily driver?? Will it be just a project car to work on and learn diesels? Do you want it as a "fix it up and sell it" project? Your car has seveal issues. No reverse is a really bad sign and the worst of all your problems. Trans rebuild may be in order and they can run from $1000 to much more for a dealer. You've got some vacuum leaks- hence the door lock problems and possibly related Climate control problems. Then of course there is the engine and whether is may need some work. Determine what you really want out of the car, take 2 aspirin and call us in the morning.

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Orland Park, IL
1985 300SD 215,000 miles