Subject: 1994 Eclipse w/ auto transmission
Question:

my trans wont go into overdrive...the car has 115,000 miles but is in very good cond. besides this 

Answer: Andrew,
The two most presumable causes are either a malfunction of the overdrive control switch, or a malfunction in the transaxle control unit (TCU). These are the first to things the dealership would inspect if you brought it into them. But since your car is out of warranty, you may want to find a local transmission specialty shop to take your car to. The dealership would most likely charge the most for any repairs.
Good luck!