JDMHONDACOUPE

I pulled my swap out about 6 months ago and the tranny was in perfect working condition no grinds,noises, or nothing smooth as butter. I didnt mess with the tranny at all it just sat covered in my garage. Now i just put my swap back in a few days ago and now the tranny will not go in reverse. I have tried everything i can think of but nothing has worked. It goes into 1-5 just like butter though. Just no reverse!! I have tried different shift linkage and everything so now im out of ideas other than taking the tranny to someone! Any suggestions or help would be greatly appreciated!