HELP- I just repalced the main and worm gear on my Craftsman chain chain drive opener. Model 13953637SRT. Following all of the instructions until instruction #4. Run the opener until the sprocket has completed a clockwise cycle. The Cycle is only 1 second and then reverses counter clockwise for 1 second and quits. I have checked and adjsuted the up and down travel controls and the up and down force limits. Is there another part that may have gone bad?

I went ahead and hooked up my chain and the hooked the door to the trolley. The opener trys to close the door when it is already closed.

Right now the chain is disconnected and my cars are outside.

Any suggestions?