4wd Doesn't engage

Diffs, axles, lockers, transmissions, portals, that kind of thing.
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montieth
United States of America
Posts: 19
Joined: Fri Jul 06, 2018 12:56 pm

4wd Doesn't engage

Post by montieth » Wed Oct 24, 2018 1:43 pm

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?
Ryan Gill
15 Recce Re-enacting Group

1943 Humber Mk IV Armoured Car
1947 Jeep CJ2A basket case
1960 Daimler Ferret
1972 AM General M35A2
x2 M514 1Ton2Wheel Trailer

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rmel
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Location: Woodside, CA
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Re: 4wd Doesn't engage

Post by rmel » Thu Oct 25, 2018 9:45 am

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 :wink:
Puller: 710K 2.7L EFI
Follower: Sankey MK 3, 3/4 Tonne
Driver: Ron // KO0Q

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montieth
United States of America
Posts: 19
Joined: Fri Jul 06, 2018 12:56 pm

Re: 4wd Doesn't engage

Post by montieth » Tue Oct 30, 2018 2:35 pm

Do any of the fittings on the piston side of the actuation system come out laterally without getting into the driveline tube?
Ryan Gill
15 Recce Re-enacting Group

1943 Humber Mk IV Armoured Car
1947 Jeep CJ2A basket case
1960 Daimler Ferret
1972 AM General M35A2
x2 M514 1Ton2Wheel Trailer

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