got my g in the dirt today. The rear and front differential lock are not engaging.
 

Hello,

I got my G in the dirt today. I first put the g in low and then lock the centeral locker. I heard a constant motor noise and then the center locker engaged (the red light came on). Then I try to lock the rear locker the yellow light came on but the red light would not come on. Then I try to lock the front same thing the yellow light came on but not the red. I try driving forward and backwards with a little turn. The front and rear lockers will not engage.

Maybe I am not doing this right. What is the optimal way to engage the front and rear lock. Should you try to engage the lockers at a stop (in drive, neutral, park) ect? But the manual said I can be going 5mph? Can you engage the locks going forwards and backwards?

How would folks engage all the locks?

The lockers can be engaged while moving. The center diff lock is vacuum operated only.

The front and rear are a combination of vacuum hydraulic. The vacuum operates an intensifier that uses hydraulics (brake fluid in a separate reservoir) to lock each diff. The front will not activate until the rear is fully locked (red light).

Have you bled the diff locks? It's done just like the brakes. The bleed screws are on the diff lock slaves which are mounted on the back side of each axle.

The first place I would look is to check the fluid level. There's a small reservoir in the engine bay in front of the driver. It's usually mounted on the inner fenderwell right next to the firewall. After that I would check the vacuum lines, and then the intensifiers themselves. They have been known to go out.

Lastly, it's possible that the rear diff lock slave has locked up with crap inside. This would require disassembly and a possible rebuild or replacement.

I've attached a schematic of the system and the WIS procedure to bleed it.

thanks.... How would you check the intensifiers?
 

Thanks Dutch.

Already check the fluid level looks fill. Also check the vac lines (visual only), but I know I have vaccum because the centeral differential works.

So... How do I check the intensifiers?

1. First. Where is it located?
2. How do you check them?
3. Can you Swip the rear to the front to check them??

thanks

1.) Directly under the car directly below the driver's seat on the inside of the longitudinal frame rail.
2.) Swap them for good ones.
3.) Possibly, but the plumbing may not reach for the swap. You'll just have to try.

When was the last time you used the rear and front diff locks? They like to be exercised regularly, or they can freeze up.

To repeat, when is the last time you bled the system?

Also, vacuum for the center does not necessarily mean the other vacuum lines are good or that the individual vacuum switches are working.

It's an overly complex system, as opposed to the very simple old W460 diff locks.