I have an '87 240 automatic wagon. When I shift into reverse, it sounds like when you're going up a roller coaster, clicking and rattling. The car moves smoothly in reverse, but still makes the noise. Today when I was driving it, I couldn't get it to go into park, and sometimes when it was in drive it would rattle a little. It is leaking transmission fluid. When I bought the car, the guy who I bought it from had put a new transmission in it but needed to have a seal fixed or something that didn't really affect the way the transmission worked. I need to know if this is something I can fix myself (I'm moderately mechanical) or if I should take it to a transmission shop ($$$!). Thanks in advance for your input.