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I have an 03 ex with auto lock/manual lock hubs. In the auto mode they pull only in the forward motion and disingage in reverse the same as any other auto lock hub. they have angular grooves in them so that when you engage the t-case and move forward they engage and are spring loaded so that they will disengage when you put it in reverse. When you turn the dial manually it holds them locked for power to the fronts in forwards and reverse. I didn't think that the vacume had any thing to do with the actual shifting of the hubs. I have a few other trucks that have vacume operated lockers and vacume operated t-cases. I can't figure out how vacume could be transfered through the rotating assembly. There have been other posts about plugging vacume ports when changing to manual hubs and I am scratching my head. Warn used to make this same auto/manual set up that they called a lock-rite. I have a set on one of my land cruisers. Someone enlighten me.
I believe the whole hub goes under a vacuum, leaving a seal in the cap, a seal between the cap and hub and a seal against the knuckle or hub shaft.
I didn't know they don't work in reverse, that sucks if it's true. However, I can't see even tapered splines slipping enough. So I suspect because the ESOF pump pulses, is that the auto works like a clip pen. Pull in once and the piece that is splined on the inside and outside engage the hub and short shaft. Pulsed again, it un-clicks and the intermediate (inner/outer splined piece) pushes away and disengages the hub and axle.
I believe the whole hub goes under a vacuum, leaving a seal in the cap, a seal between the cap and hub and a seal against the knuckle or hub shaft. Correct
I didn't know they don't work in reverse, 4WD works forward and reverse that sucks if it's true. However, I can't see even tapered splines slipping enough. So I suspect because the ESOF pump pulses, is that the auto works like a clip pen. Pull in once and the piece that is splined on the inside and outside engage the hub and short shaft. Pulsed again, it un-clicks and the intermediate (inner/outer splined piece) pushes away and disengages the hub and axle.Good description and basically how it works.
I appreciate the info. I have at least one hub that is not dis-engaging. I tried to turn the front drive shaft by hand while the case is dis-engaged and it won't turn. I can hear it binding on the pass. side. I have a slight vibe that is very noticableat about 75 + mph and I'm hoping this is the culprit. I was going to change to warns but these hubs are handy if they would just work right. I posted earlier that they didn't pull in reverse. That was an assumption based on how other non vacume auto hubs work. It is muddy at the farm today so I did a few doughnuts spinning mud forwards and backwards. I stand corrected.
This may seem like a dumb thing, but check the vacuum lines. My hubs both randomly quit working on me and I couldn't figure out why. As I was replacing them with the warn Hubs, I noticed that one of the vacuum fittings (the one in the wheel well where the hard rubber line mates to the flexible rubber line) had cracked off behind the bracket and thus the vacuum pulse was never getting to the hubs. A quick look and a $10 part could have saved me a lot of time and expense. It may not be your issue, but its worth a look.
Also, I believe you can figure out which hub is the culprit by spinning the stub shaft CV joints in the steering knuckles. You might even try rocking them back and forth to see if you can get the hub to disengage. Its a fast thing to try before you tear apart the hubs replacing seals and such...
After just doing the Guzzle maintainence I can explain well how the hubs work.
The rubber "plunger" touches a system that works like a push button switch. When you push it in part-way, there are steel tines that catch on tabs that hold the hubs in a locked position. When you push it in further, the tines unhook and the plunger can retract all the way to the "free" position.
When you manuall lock them it just mechanically pushes the plunger into the engaged (locked) position.
Basically, to lock, the plunger moves in about 3/8" to catch on the first set of tabs and stay in that engaged position. To unlatch, the plunger is pushed in an additional 1/4" (5/8" total) which allows the tines to pass over the first tab and past a second tab that allows the plunger to fully retract back to free.
Think of it like the push-button pen. Press it a little to expose the pen, push it again further to retract it.
Hope this helps. I spent 10 minutes searching for an animation of how the push button switch works to use as an illustration, but I couldn't find anything.
I appreciate the info. I understand the inner-workings now and I think i'll try to repair them. I was looking for some kind of illustration but no need now.
I appreciate the info. I understand the inner-workings now and I think i'll try to repair them. I was looking for some kind of illustration but no need now.
Do not attempt to remove the rubber diaphram. If you do it will be destroyed. You can clean the gear / internals but don't try to work on the diaphram. I also used silicon spray lube on the external auto/manual selector spraying into the joint to allow lube to enter. Then I worked the switch until it was smooth again. Rotate the hub so the lubricant can run around the inside while moving the switch.