Craftsman 1/2hp 13953657SRT

Replaced gear assembly due to wear and tear and malfunction, gears worn completely off.

Everything appears to be re-assembled correctly but travel of unit is 8" down and 8" back up, without door attached.

Safety sensors are green and remain green through cyle.

Downward and upward limits are not even coming in contact with the unit sensor. The force settings seem to have no effect on travel. I have adjusted chain to see if it would affect and no luck seems to be fine, no binding or sag.

Could this be the motor?

Looking for any help possible.