I can assure you the sub $100 solution I suggested will, by far, be the cheapest attempt at a fix, and that is all that it is, an attempt. With the age of the car, it should have been changed anyway, so why not try it? You could start replacing thousands of dollars worth of transmission components instead, but it doesn't make much sense to me...

Not sure why I said royal purple above, I used mobile1 5w20 engine oil in both of my cars...