we have a car that when it's semi-cold out (0 celsius) that if you shift out of park, and into drive, it won't shift with you

the car won't move, like it's in neutral, and then eventually if you leave it for a while in gear it'll "catch" and then the car will start to shift..

 

Check the fluid to make sure its full. When was the last time it was flushed?

 

yes it's been filled up..but i don't know when it's been flushed..

also why is it a dark colour instead of bright red? i remember someone saying it's because it's being burned or something?

 

burnt tranny fluid is a bad sign. ur tranny is probably fuxored.

 

i guess it's slipping a lot now and burns up the fluid..

can i rebuild it myself or is it best to let a shop do it?

 

If you're not familiar with it and you don't have the specialty tools, let the shop do it. Most of the time you get a great warranty with it too