Toyota Repair: transmission, transmission problem, transmission fluid

Question
when car is put down for short spell and come back stat and you put the car in reverse
or drive is selected it delay for a couple of seconds and then engage can you tell me what could the cause

Answer
Check the transmission fluid, do this with the engine at operating temperature and running at idle and in PARK, if the fluid id low add fluid and check for a possible leak, if the fluid is dark and smells burned then there may be a major transmission problem.