My civic keeps slipping out of gear and seems to go into neutral, as soon as my temp gauge goes to about half way, I just recently changed the thermostat. I purchased the car from someone that didnt take care of the car at all. I also recently put transmission fluid in to see if that was the problem and that did not solve it. Can anyone tell me what might be the problem, I can provide more information if need be.

 

Need to be more specific. What gears do not work? Is the engine and transaxle original to the car?

If you added fluid where is it leaking from? What was the condition of the fluid?

 

If you put fluid in and there is no leak you might have over filled it. Check the level, and drain the excess out. It could be a miss adjusted cable as well. I am not the best with auto transmissions. But I know someone here should know a lot more. These are the basics fluid, and cable adjustments that I know to start with. Hope it helps