So I bought a rebuild trans- 4l60E -it was driving shifting perfect for small trips less than 5 mi. first time on the highway about 15 mi. running fine on the way home I pulled up to a light stop and DONE will not go into any gear wont hold park nothing. So I tow it how and now If I start the truck run through the gears nothing- not even the old chevy clunk- but when I try to go back to park it starts grinding.What could cause this??? Any help is great Thanks