I noticed there is a bit of a delay when i shift from any gear into reverse, Im guessing because the teeth on the gears are getting worn. can I just replace the reverse gear or would i have to get my transmission rebuilt?

 

Or do i not even need to worry about it?

 

All gears in an automatic transmission are always engaged. Reverse and forward gears, all are engaged all the time. Automatic transmissions do not engage and disengage gears. They employ clutches and bands to hold different parts of planetary gearsets to create reverse and all the forward ratios.

This probably doesn't make sense if you don't have any automatic transmission background. You can get a good understanding of how an automatic works at http://www.howstuffworks.com

If the delay is more than two seconds you could have worn seals or a bad electronic pressure control solenoid (EPC.)