Ishtiak

My Toyota Carina my road 1991 model it is facing reverse gear problem.In the morning the car goes in reverse gear but if it kept in. Cold about a hour reverse gear don't work.it needs to run in forward about 5 Km then the reverse works again and if reverse works for a time it always work until rest of more than 1 hour.so in cold it doesn't work but in Garrard morning it works and in hot or running also work so please help me that what I can do