1987 Camry SW: Automatic Transmission Problems

I just picked up a 1987 Camry Station Wagon. The automatic transmission seems to shift ok in forward gears but it appears the transmission is on it's way out as it has difficulty shifting into reverse. Can someone confirm this? Is it possible to do a rebuild on the transmission or does it need to be replaced? What do the independants get for doing this type of repair? The fluid is dark brown which is also not a good sign....