Diff locker? or 4wd actuator? (pics)

FYI, while I couldn't get the 4WD to engage in high gear it does work automatically when I shift to low gear, and the 4WD dash indicator does come on.
Apparently I don't have a problem with any vacuum hoses or actuators. I'm guessing the switch on my 4WD button is dead.

 

The vacuum pot on the front diff slides a synkro ring to engage the right axle to the short stubb shaft coming out of the differential, and engages four wheel drive. At the same time you engage the front differential, there is a corresponding vacuum pot at the rear of the transfer case which engages the front drive shaft to the transfer case gear set. This is the way it is on my 93 Jumbo. If you want a front locking diff, you can weld the spider gear to the side gear, and because of the front driveshaft disconnect the front diff acts like an open diff, until you engage four wheel drive then its all locked together. I had my front diff apart and measured the excess clearance between the spider gears and the carrier, which was .008 inch, then I bought some .008 steel shim stock and made cup shaped shims to go behind the gears. This method will still allow some differential action under turning loads on pavement but will for all intents and purposes be a locked diff when on dirt. The down size? Turning in four wheel drive is a bit tougher.

 

If you shim the spider gears in the front differential until the are firmly engaged with the side gears, then have the front differential engage independently from the transfer case, you end up with an effective front semi locker. I used .020 shim stock behind the spiders and it is basically a locker now. Use the same vacuum control as the rear locker uses and Bobs your uncle.

 

I figure locking up the diff like this would lead to problems if expecting any extended time without problems arising. The steering would also become affected and causing affects imo. I guess I’m old fashioned and usually like to repair as OEM and have faced flak from being this way. I think that most on here like to keep their machines running as OEM meant it to be and worried that those not trained in the mechanical field might think these mods to be perfectly fine for everyday use. Just me and my opinion and I’ve been wrong before.

 

I just rewired my difflock switch straight to a switched power source, no I can lock it in any gear at any time. It great when in mud and one needs second or third gear wheel speed. If you want a front locker, just weld up the spider gears, disconnect the front axel wiring from the transfer case wiring harness and wire. The front axel engagement switch to a dash mounted switch in a similar fashion to the rear diff lock. The differential in a diff lock configuration has the left axel permanently connected to the crown gear, when one engages the diff it simply locks the right axle to the crown gear with a slider connecting the axel to a stub shaft at the crown gear. The exact same thing takes place in the front differential but the left axle is connected to spider gears in the carrier so when in four wd power can go to the wheel which spins when traction is low and not to both wheels.