I dropped both lower units today, replaced impellers and put new props on both. Basically same procedure followed for both, so I thought. Port motor (1B043974) will not go into gear now, while starboard works fine. There's no resistance on the shifter for the port motor. I removed the cowling and can see the cable actuating the shift mechanism on the side of the powerhead, but nothing is happening down below. Regardless of shifter position the prop spins by hand with no resistance in either direction. I am assuming the upper shift shaft did not engage the coupler to the lower shift shaft when I reinstalled? Just looking for some guidance on rectifying this. Port motor is a counter-rotating unit. Thanks!