Passat Wagon GLX reverse problem

I own a 1996 Passat GLX wagon with auto transmission with 86,000 miles. The car runs fine except lately when I put the car in reverse, the transmission doesnt seem to catch until my engine revs up to 3000rpm for about 5 seconds. When I am parked on an incline facing downward, my car is unable to back up at all. I figure this is obviously a tranny problem, but I cant tell if I need a simple trans fluid replacement, tuneup, or if it needs to be replaced completely. I haven't taken it to a dealer since they never seem to diagnoss a problem without replacing every part associated with it. The car runs fine otherwise. Please reply with any advice or suggestions. Thank you.

It may be as simple as low fluid, as on that transmission it is very difficult just to check the level. Take it to someone who is familiar with VW automatics.