First, thanks for all the comments and help!
I got the third channel working today! I think I may have had something pressing on the servo when I put the cab back on, because the pinion gear did not line up as good as it had when I originally fit it.
And, it is colder that CRAP here in iowa today and SNOWING! We are setting records for late year snow accumulation, man I am sick of winter! So, I did not take any video on the loading wall.
. And, my brief testing with the pinion not lined up quite right caused a bit of binding and the shaft unscrewed from the servo. I'll be taking it apart to fix that so, if you are still reading....
Is it more common to use a big long chain around the slew ring gear and drive the chain with a pinion, or like my initial attempt of driving the ring gear directly with the pinion?
If I can figure out how to keep an o-ring on the slew chain ring it seems like that might work better? I have a perfect pinion pulley that would work good on the servo, front wheel from a slot car is actually an o ring tire on the rim with a set screw for the shaft! I would just need to fit or modify the ring gear with a grooved slot or ring.
Jim