Hi All ! Tks for the reply .
Yes my motor is aligned in good shape
For the shim I think should be ok , but I am still not sure , maybe need to reopen it out again , tks for the advise .
For the battery is not a stock , due to this gun is my own custom build , so the battery is buy separately , I am using 11.1v lipo stick type battery , so before I open the gear box out , the battery is not that hot , just keep warm only , so no idea why now , but I will open the gear box again .
So thanks again guy's .
Your advise is very usefull for me .