2009 Tundra 4x4 issue help needed please ADD or Transfer case actuator

Hi All,
I've seen and read many discussions on this forum regarding the ADD (front diff) actuator and transfer case actuator troubleshooting but am looking for advice on my specific issue.

Here's the low down.
Was on a small bush road and selected 4hi. 4hi started flashing. Stopped and tried 2wd/4hi/4low in park and neutral. 4hi continued to flash. Continued on my way. When I got to the pavement at higher speed, noticed a kind of ticking noise.
At home, noticed the front propeller shaft engaged (transfer case in 4x4) but from axle not engaged. I also noticed a "beeping" sound coming from the ADD. Took ADD off, noticed the yoke in the 2wd position. Removed the cover and motor from the ADD. At first I thought the worm gear was stripped, but after I clean it up realized it wasn't stripped, but was gummed up a bit with rust and hardish grease. Cleaned it all up, cleaned the motor armaure and filed the brushes, placed the yoke in the 4wd position and reassembled. I hooked up the connector and let the ADD dangle to see if it would move. Put the switch in the 4hi position and started the truck. Nothing happened and 4hi still flashing. Cycled the switch a few times, still nothing and 4hi still flashing. Turned the key off. Once the key was turned off, the yoke on the ADD moved to the 2wd position!! Started truck and the 4hi was not flashing. Cycled the switch, the ADD yoke cycled as commanded back and forth and 4hi still not flashing. Everything seemed to be working properly. The transfer case is now disengaged (front propeller shaft turns freely). I then realized I didn't check if the vent hole in the ADD cover was cleared out, so I decided to remove the cover to check. Cleaned out the vent hole, and reasembled the ADD. I let it dangle again and to check it with the switch. Now it doesn't work (yoke doesn't move) and the 4hi is flashing again. I put the ADD back on the bench and put 12v to pin 1 and 2 and the actuator does work in both directions.
Whenever I remove the black cover, I noticed it is slightliy under load. There's a spring under the plastic gear, and the position of the gear must place the metal strips differently when assembled?? I'm wondering if the first time I just got lucky with the correct clocking position, and I didn't get it right the next times, or if something else is going on.

If anyone knows how to correctly clock the cover when assembling the ADD cover, please let me know.

Any advice would be truly apprciated. I'm on the verge of buying a new ADD but not entirely sure my old one is bad, might just be the way I install the cover. Or, maybe something elase is going on?

Thanks!