little bit of a problem

[tjcnok]

1993 Ranger V6/Automatic. Starts easy, runs great. Not used very much any more. Stays parked 90% of the time. Slightly a little over 15,000 miles. When I start it the choke seems to work perfectly but the 1st time in reverse the engine speeds up a lot and it shifts really hard. Mechanic says it needed the trans. fluid and filter changed (132.00). Still does the exact same thing. Any on want to guess what is really wrong and how to cure it, besides changing mechanic's, lol. Thanks