New member to FTE. I've got a 2003 F350 DRW with the 7.3. The starter was bogging down so decided to replace it. Didn't realize that there were 12 and 13 tooth starters. I bought a rebuilt Ultima from OReilly's not realizing it was a 13 tooth. Installed it, barely, and it make a racket. Tried it again and nothing. No lights when key was turned to start. I counted the teeth on the old one and it was 12. There was a slight design difference between old 12 and newish 13 tooth. Took that one out and installed 12 tooth. Made sure all connections were solid. After connecting the passenger ground I heard a pop. Checked all the fuses but none were blown. Bench checked relay and it seems to work fine. I've been messing with it a little bit at at time when I can. Fast forward to today..installed 12 tooth after having it bench checked at OReilly's. On first attempt, I forgot to reconnect the disconnect that replaces the fender mounted solenoid. When I connected the driver battery ground, the starter began to spin. The key was not in the ignition. Second attempt was after reconnecting the disconnect. Connected passenger battery ground and starter spun up again. The key was not in the ignition. I'll check fuses again tomorrow.Other than replacing the positive harness for both batteries, I'm asking for some help. Thanks.

 

The consensus is never buy a box-store reman starter. The real Denso ($335) https://cncfab.us/i-30497609-denso-g...8000-8420.html
or a Motorcraft https://www.rockauto.com/en/moreinfo...362631&jsn=455 is all I'd trust to not have to go through doing the job multiple times.

Sounds like solenoid is wired backwards if it tries to start by hooking up the batteries.

 

Agreed! The track record is terrible and people always have issues.