4wd Doesn't engage

[montieth]

What's the procedure for trying to figure out what's going on with 4WD?

With the truck up on stands, the 4WD doesn't appear to engage. Driving on soft ground likewise. There's a new switch in the left side of the Witches Hat and it illuminates the light when you ground the connection at the switch cover.

I've checked the function of the slave piston (and bled it). It gives a decent 2 finger joint movement.

The sprung pushrod is free to move.

But the actuation doesn't appear to happen inside the witches hat.

The position of the muffler makes getting into where the switch is it difficult without pulling the muffler and that's not easy since it's old and rusty. Is there a part I can easily withdraw from the right side of the truck to get into the witches hat to see if the arm or toothed collar is busted?

Or are we down to dropping half the drive line to get into the witches hat?

[rmel]

You should be able to get a view in there with a Borescope.
How deep in there will depend upon how much you want to spend.

There's a number of choices from USB to WiFi connected, various
resolutions and probe diameters. The small diameter probes with
reasonable resolution (e.g. VGA) are expensive, the larger the dia. the cheaper.
Ranges from ~$30 to $3,000. I have several, cheap ones and a more
expensive PCE-VE 200 that was about $300, with a probe dia. just
under 4.5mm (0.18"). Amazon has a broad range of choices. You
might get luck and find one small enough to follow the place of the
pushrod and see what it sees.

These scopes have helped me diagnose several problems W/O
having to do unnecessary exploratory surgery

[montieth]

Do any of the fittings on the piston side of the actuation system come out laterally without getting into the driveline tube?