D7-17A final drive hub questions

Hi AOI,
1/
lock #5 appears to be removed already, maybe stuck in outer cap bore by grease--plate with hex shape that slides onto the outer bearing housing retaining nut, and is stopped from turning by 2 pins
The plate is able to be reversed, if needed, to index it to align the dowel pins and nut hex after tightening the nut.
This nut does not adjust the sprocket bearings.
A normal 1" drive socket or large wrench will turn the nut to 500-600 pounds feet torque.

2/
it is difficult to turn the big castellated sprocket bearing nut without a "C" spanner. You can try and lever it around with a crow bar suitably supported by blocks on the flat track frame upper surface--be careful, the bar can and will slip if you take too big a bite at a time.
To turn the castellated nut you must also remove a lock bar that is positioned below the castellated nut behind the track frame.
To tighten the bearing adjustment you must turn the castellated nut counter clockwise this applies to both sides of the machine.
This adjustment is given as turn as tight as possible using a 5' extension on the "C" spanner, this equates to around 500-600 ponds feet also--100 lb man on a 5 foot extension.
Hope this helps.
Cheers,
Eddie B.

You are loosening the wrong part. The big nut on the end doesn't get loosened. The pinch bolt gets loosened, and the lock which is the tab that locks in the tooth of the adjuster ring gets removed. Also you need the proper spanner wrench. I believe OTC makes the right one. Also, I removed two or three grouser pads, to allow the spanner wrench to not have to tighten the nut while being on an angle.