ey there forum folks. I'm a newbie here, but I've been a professional mechanic now for 45 years. Bought a 21' Marlin cuudy cabin w/a 305 Chevy & OMC cobra for $400. Trailer & all. The guy had put 1000's into it to end up having to back up all the way to the dock. Got disgusted & sold it to me. That's where my nightmare started. Read all the info I could about these drives. Watched all the Youtube videos. Removed the 1st drive & replaced the gimbal, input shaft, shift cable, etc. (input ujoint shaft was twisted!!) & put it back on to find out the prop shaft was bent. Ok, decided to get good used unit rather than rebuild this one. 2nd unit ended up causing a thumping noise. We lost fwd with it and ended up having to back up to the dock at a lake. Bought a super clean 3rd. unit w/low hours & fresh water use only and decided, ok....its time for me to learn how to rebuild these things. I took the unit apart. Inspected the upper drive. Gears looked beautiful. Perfect tooth pattern. No leaks from the front seal going into the bellows. So, I decided not to mess w/the upper unit other than replacing the water pump seal & large oring. New water pump. Took apart the lower unit & the gears looked great. The area where the dog clutch engages were like new. Nice and square edges. The dog clutch was hardly worn. I decided to install the new updated detent & new dog clutch. Reassembled it w/new propshaft & shift rod seals. Bearings & gear pattern looked awesome. Got it all together & set the shift rod at 8 turns in. I also measured the height as well. 6.904 if I recall. I looked it up. Spoke w/Wayne Koll up in Canada from TC electronics & Marine. He's the one who said 8 turns for the shift rod adjustment. Ran the boat a couple of times new another new cable & it was fine until last night. Was out in Long Beach Harbor net hooping and the drive was going in & out of reverse & fwd no problem. ESA operating properly. Hours later, all of a sudden, after a reverse shift into forward I lost forward. Started grinding like it didn't have enough throw to go into gear. I had reverse though. Out on the ocean, I opened the engine cover w/the engine idling. Removed the shift cable connection & pushed the cable in. Went into reverse & the ESA was working. Tried to pull it into forward and same thing, grinding...no forward no matter how much I pulled the cable out. I believe this boat is cursed. I cannot believe that after 3 drives and having gone into the last one that all my problems are related to the drive. Wayne had mentioned to make sure to use a genuine OMC shift cable because he said there's been issues with the aftermarket ones stretching & then losing forward. This cable is literally 2 months old. This is the last time I'm pulling this drive off. I'm either going to find the reason why this thing keeps having these issues, repower the thing with a Mercury unit, or just sell the boat. I'm done. My mental sanity is at stake here. Any help would be appreciated!