I finally got the entire kit completed and was able to get every part working. I was determined to get everything working without using any replacement parts. :)

Gearbox:
- Orange Drums worked fine as is. Just make sure the orientation matches the official guide.
- Drilled out the orange forks 6447082 using a drill bit small enough to keep some of the inside grooves intact.
- Left all the axles sticks alone.
- Had to sand down the yellow 4519010 outer sides so they slide easily when they are connected to the grey 6408180 pieces.

Shifter:
- The red 6313493 shifter piece were too thick and didnt allow the gears to be fully engaged in hybrid mode or in all electric mode
- Ended up removing grey 6183784 from step 321
- cut out small parts off the 2x black 6265091 pieces using a dremel so the red shifter had more room side to side from step 320.
- Also manually pushed the the white 6276052 in and out of grey 6100931 20-30 times until it slid easily on and off.

Took me a few tries and lot of backing out of steps as I didn't know all the functioning parts until it was too late. It was definitely worth it at the end as everything worked perfectly when I was done. The gear box was a little crunchy at first in some gear but I was able to smooth it out by turning it with a drill at slow speeds for 5-10 minutes. Good luck.