1991 Toyota 4Runner transmission

i recently bought a 1991 4 Runner for a couple of hundred dollars. i knew it needed work but i could not pass up the deal. my engine purrs like a cat, but when i engage the gear selector lever from park to any other gear, the vehicle feels as if the transmission engaged but it does not move either forward or back. i changed the transmission fluid and filter already. i ask if you guys can assist me with this issue. i have the money to drop on a mechanic, but i would like the experience of fixing this vehicle myself.