i finally got one, there is a bit of a rim on the back part of the sprocket so it wont come off that way ,so i had to take the brass fitting on the gear end to remove the whole assembly ,l i hope this helps someone else who does this i guess Trumpeter had something else, you can see the rim just inside the sprocket
thanks for your help everyone i hope to save for some new gearboxes and electronics to get it going again, i'm sure i will be bugging all of you again for help...lol