They're called "Lock-O-Matic"s. I had a set on a OlllllO back in the early '80's. (Warn's attempt to take the "next step" in hub technology - "shift on the fly", back in the 70's ('60's??))
The way they work is, they have a nylon "FRICTION SHOE" ring inside of the hub. This ring looks like a gear ring, with little blocks (INSIDE surface) instead of teeth. If you have your hubs set to "AUTO" (normal "street" mode) & shift your TC into 4WD without locking the hubs, the clutches engage WHILE THERE IS POWER TO THE AXLE. When you coast or brake, they disengage; then re-engage when you get on the gas again. When you are in 2WD (NO power through the front axles), they remain unlocked. I remember literature (they were still sold back then) that said that it was primarily an ... "emergency" - type setting (not really intended for extended / HD 4-wheeling use) ... like, if you are running down an unimproved road, round a corner, and end up in all kinds of mud, etc where you wanted 4 WD to get you onto firmer ground, but didn't want to stop, get out, lock hubs, etc ...
Of course, the weak-point was obviously the (nylon) friction shoe ring. If you ever actually PUSHED them (not really THAT hard), they would strip the blocks off the ring, and spin. (Sounded like a model 20 rear spinning an axle). After replacing about 3-4 sets of the clutch rings (they were a standard repair-kit sold by warn, and kept on-hand by anyone who sold warn hubs), I finally just considered them "Hand-Lockers", and never used them in "Auto" mode (as in, "Shift into 4WD on the fly") again, and replaced them with standard warn locking hubs as soon as I could. From what I can remember, unless you did a complete disassemble, super-clean & rebuild; once you blew a hub, then you would keep blowing hubs. Also, failure to SUPER-maintain the hubs tended to lead to a blown hub (from remembered conversations with other 4-wheelers, mechanics, and parts guys who had dealt with them).
They have 2 settings, "Auto" and "Locked". Locked is .... "Locked" (normal locked for hubs). "Auto" is "Unlocked" until you: A) Put the TC into 4WD, and B) ONLY when you are accelerating / pulling. Does NOT allow you to 4WD compression brake (You can Comp-brake, but only the rear 2 wheels will actually "pull" - the front wheels are disengaged and free-wheel).
The simplest way to tell if they are REALLY OK is to start to take the hubs apart, and look for the "clutch ring" to be intact (all the blocks in place - simetrical, and no parts floating around). IF they are all there, then, have them re-assembled, and use it as a normal locker (YOU lock by hand when you need it) UNTIL YOU CAN REPLACE IT. Out on the trail is no place for the hub to blow, especially since you can't get the clutches any more. Plenty of people here can give you better advice than me on the best hubs for an FJ. I just know that the aisan's on mine work.
BTW - a quick check; I couldn't find any friction shoes for warn lock-o-matics; BUT - here is a D/L PDF about them / disassembly / repair, etc:
http://ww2.justanswer.com/uploads/heavychevy396/2010-01-18_143954_warn_selective_lock_o_matic.pdf
Good luck
PS - I think the difference between "Select-o-matic" & "Lock-o-matic" hubs is about the same as the difference between a Ford Taurus & a Mercury Sable. Basically just a different name, for business reasons. (i.e. - Manufacturers wanted "Select-O-Matics" as a dealer option, and after-market could buy "Lock-O-Matics"). I've never seen anything definitive that shows a difference between the 2. Just my $0.02
The way they work is, they have a nylon "FRICTION SHOE" ring inside of the hub. This ring looks like a gear ring, with little blocks (INSIDE surface) instead of teeth. If you have your hubs set to "AUTO" (normal "street" mode) & shift your TC into 4WD without locking the hubs, the clutches engage WHILE THERE IS POWER TO THE AXLE. When you coast or brake, they disengage; then re-engage when you get on the gas again. When you are in 2WD (NO power through the front axles), they remain unlocked. I remember literature (they were still sold back then) that said that it was primarily an ... "emergency" - type setting (not really intended for extended / HD 4-wheeling use) ... like, if you are running down an unimproved road, round a corner, and end up in all kinds of mud, etc where you wanted 4 WD to get you onto firmer ground, but didn't want to stop, get out, lock hubs, etc ...
Of course, the weak-point was obviously the (nylon) friction shoe ring. If you ever actually PUSHED them (not really THAT hard), they would strip the blocks off the ring, and spin. (Sounded like a model 20 rear spinning an axle). After replacing about 3-4 sets of the clutch rings (they were a standard repair-kit sold by warn, and kept on-hand by anyone who sold warn hubs), I finally just considered them "Hand-Lockers", and never used them in "Auto" mode (as in, "Shift into 4WD on the fly") again, and replaced them with standard warn locking hubs as soon as I could. From what I can remember, unless you did a complete disassemble, super-clean & rebuild; once you blew a hub, then you would keep blowing hubs. Also, failure to SUPER-maintain the hubs tended to lead to a blown hub (from remembered conversations with other 4-wheelers, mechanics, and parts guys who had dealt with them).
They have 2 settings, "Auto" and "Locked". Locked is .... "Locked" (normal locked for hubs). "Auto" is "Unlocked" until you: A) Put the TC into 4WD, and B) ONLY when you are accelerating / pulling. Does NOT allow you to 4WD compression brake (You can Comp-brake, but only the rear 2 wheels will actually "pull" - the front wheels are disengaged and free-wheel).
The simplest way to tell if they are REALLY OK is to start to take the hubs apart, and look for the "clutch ring" to be intact (all the blocks in place - simetrical, and no parts floating around). IF they are all there, then, have them re-assembled, and use it as a normal locker (YOU lock by hand when you need it) UNTIL YOU CAN REPLACE IT. Out on the trail is no place for the hub to blow, especially since you can't get the clutches any more. Plenty of people here can give you better advice than me on the best hubs for an FJ. I just know that the aisan's on mine work.
BTW - a quick check; I couldn't find any friction shoes for warn lock-o-matics; BUT - here is a D/L PDF about them / disassembly / repair, etc:
http://ww2.justanswer.com/uploads/heavychevy396/2010-01-18_143954_warn_selective_lock_o_matic.pdf
Good luck
PS - I think the difference between "Select-o-matic" & "Lock-o-matic" hubs is about the same as the difference between a Ford Taurus & a Mercury Sable. Basically just a different name, for business reasons. (i.e. - Manufacturers wanted "Select-O-Matics" as a dealer option, and after-market could buy "Lock-O-Matics"). I've never seen anything definitive that shows a difference between the 2. Just my $0.02
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