Just did some looking, and according to some guys on Facebook, the TJM ProLocker was just a licensed design from Jack McNamara. I need to do more checking, but on the surface it seems like this is essentially the same thing:
Which Locker ??
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mudgudgeon
Resident galah
McNamara developed what is now the TJM Prolocker. There's old video footage of the early prototypes on YouTube I think.
ARB locker was an adaptation of the design if memory is correct.
The ARB airlocks came first according to my research. Designed in the 1980’s by Tony Robert’s. 1987 is when ARB bought the rights and began calling it ARB Locker. First one apparently installed here in the USA in 1990. In 1991 I saw a demo display in a vendor tent at a Californian 4WD Assoc sanctioned event. I’ve had double ARB’s in my 80 axles since 2010 originally installed by the PO. I have never had a problem with them. A couple years back I tore up the front ring and pinion so while I had it apart for repair I disassembled the ARB to inspect it and learn how it works. I can’t imagine a simpler design. I decided to replace the lock ring, internal bonded seal and convert from the older coil type return springs to the single wave type return spring, The bonded seal, which is actually the engagement air “piston” looked as new as the new one.
The design is simple and fool proof. ARB might have had some QC issues over the years not unlike manufactures of myriad other products. That, and installer induced problems, not the design or strength of the unit would most likely be the sources of owner headaches.
ARB lockers are great when new, it's just the air leak problem. You've got seals on moving surfaces between the seal housing and the casing, to transfer air to the locking ring. The seals wear over time, and air will leak into the diff housing, causing all kinds of dramas. Well known, not a new problem. This video shows the design, you can see the failure potential:
TJM Pro by comparison just has an air line running straight to a sealed actuator, no rotating seal. It's shown to be much more dependable over time when it comes to air leaks.
For comparison, here's another short video showing the TJM Pro locker operation. There's a spinning plate nested between a couple of prongs connected to the actuator. When air pressure is applied, the actuator forces the plate to move, engaging the locker. A spring returns it to an open diff when air pressure is removed:
Much better design in terms of air transfer.
Much better design in terms of air transfer.
Ehhh, might as well go all the way. Here's a video showing the operation of the Harrop/Eaton elocker design:
I honestly see little reason to go air over elocker these days. It's essentially the same thing - pushing a locking plate into place on demand. Whether that's done by air or electromagnet is really inconsequential. Its much easier to route electrics though, there's no air leaks to worry about, and it's easier to repair wiring than air lines. Hell, for a trail fix, you could power an elocker from a clip-on 9v battery at the housing.
I honestly see little reason to go air over elocker these days. It's essentially the same thing - pushing a locking plate into place on demand. Whether that's done by air or electromagnet is really inconsequential. Its much easier to route electrics though, there's no air leaks to worry about, and it's easier to repair wiring than air lines. Hell, for a trail fix, you could power an elocker from a clip-on 9v battery at the housing.
I don’t think you read my entire post. Lots and lots of use since 2010 and I never had a problem. Due to this sort of hubub I decide to tear my front ARB apart when the diff gears got destroyed so I know exactly what’s in there. It all looked fine and was operating fine the day I disassemble the ARB unit. That was some 13 years post installation. If the design was no good they would have never became as prolific as they have.
Being that illiteracy is on the increase despite the rising cost of “education” and the ever increasing number of “college graduates” you can expect the quality of all products you buy to decline as time passes.
I understood what you wrote, I was more just running through the detail for the other viewers of the thread. Easier to show the design to everyone with a 40 second video.
As for your particular case, I'm glad yours has been problem free. Plenty of other people have had the same experience. It's by no means universal though. Plenty of other people have had problems, repeatedly. As for why one has problems when another doesn't... well it's a rubber seal against spinning metal. Temperature, oil brand/impurities, driving frequency and conditions, manufacturing batch/qc issues with the rubber, machining imperfections in the housing, wear marks on the sealing surfaces, etc etc. That's why I posted the video, one person's experience is never the whole story. Look at the design and think about it. From an engineering perspective, one design is more prone to air leaks over time than the other, it's self-evident. It doesn't mean the ARBs design is "no good", but in my opinion, the TJM Pro design is superior.
Let's put it another way - what other rubber o-rings in your vehicle would you trust to hold an airtight seal under pressure on a rotating shaft after 13 years?
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hoser
SILVER Star
IMO, I would lean towards ARB for hard/competition use and Eaton/Harrop for standard use seems more reliable. That said, I have (6) ARB lockers and two of them have internal air leaks that need addressing and would give Eaton/Harrop a try on my next build simply because it is a bit of a PIA to service the locker. I wouldn't consider TJM in the U.S. due to all the defective units when they were first introduced in the US and the current lack of support.
Edit: Video deleted
Edit: Video deleted
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That Eaton locker shown in the video is a totally different design to the ones I've seen from Harrop for the 80 series (IE, compare to the video I posted above). I can see why that design would be problematic and failure prone (especially if engaged while spinning), but it's not reflective of the actual ones that Harrop at least produce, for the 80 series or any other vehicle. My understanding was the Eaton ones state-side for the 80 are essentially the same design as the Harrop, but I have no experience with the Eaton ones to confim. Anyone here have insight into that?
hoser
SILVER Star
I haven’t looked at the Harrops in a long time. You’re right, those Eatons in the video are quite different. I’ll delete the video so as to not confuse anybody.
I understand the Harrops are a modified Eaton lockers and was for years. Eaton supplied the them to Harrop. Only fairly recently did Eaton offer LC lockers in the US.
I would also like to know how US Eatons differ from the Aussie Harrops.
I understand the Harrops are a modified Eaton lockers and was for years. Eaton supplied the them to Harrop. Only fairly recently did Eaton offer LC lockers in the US.
I would also like to know how US Eatons differ from the Aussie Harrops.
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The seal housings that transfer air pressure from the copper tube into the internal air chamber of the ARB carrier uses the same concept as every shaft seal on our 80’s. It seems that ARB might have shot themselves in the foot with regards to good ole give a crap in the quality control department during recent years.
I’ve been driving on these for almost 30k miles. The torque is equal across the axle. It’s because the torque is what equalizes the tire rotation.
One of the first things I did after installing them was to go to an abandoned parting lot after a foot of snow had fallen. Kaisers front and rear, center diff unlocked and carved up that lot like a cat on a carpet.
My first 80 had e-lockers and in comparison were pathetic.
That's where the LSD would help, but yeah, if you're not going in a straight line lockers are tricky. I'm guessing you've got an auto though? Not sure the experience would be the same in my manual.
All the magic happens in the diff. I don’t see why having a manual would be any different.
When I first installed these I installed a spool in the center diff. Seemed logical from what I read on this forum. Waste of time and money.
Went back to a stock center diff and it was such an improvement. Instead or each axle balancing themselves all four were balanced together.
4low with the center diff unlocked had great traction and exceptional maneuverability
If I had to build another 80 it would be the same as this one.
kaiser and eaton/detroits are similar auto lockers
^^i have similar experiences, about the only situation I can think of where a selectable locker is better is when doing some serious rock crawling, but even then you'll get your steering bound up and have to unselect the locker to turn, where as an auto locker will automatically do this when your off throttle in a steering situation.
Caveat....i dont rock crawl
^^i have similar experiences, about the only situation I can think of where a selectable locker is better is when doing some serious rock crawling, but even then you'll get your steering bound up and have to unselect the locker to turn, where as an auto locker will automatically do this when your off throttle in a steering situation.
Caveat....i dont rock crawl
B..b...but... I want a little button to press to turn it on and off 
In all seriousness, the Kaisers are interesting, but I'm not sold on them yet. I've heard mixed things about their on-road characteristics, but I need to research them more.
mudgudgeon
Resident galah
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With a manual transmission you can take the load off the driveline momentarily with the clutch which allows you to turn when the front is locked up.
Many times in rocks, I've stabbed the clutch in to get a decent bite on the steering before releasing the clutch and getting back on the throttle
With a manual transmission you can take the load off the driveline momentarily with the clutch which allows you to turn when the front is locked up.
Many times in rocks, I've stabbed the clutch in to get a decent bite on the steering before releasing the clutch and getting back on the throttle
ARB all the way
ARB does not need any promotion just look all over the world what most race teams are using
only complaint i have is that damn cooper tube i already chewed up one but now i bolted it to the case and there is no way it can move back in to the ring gear
ARB does not need any promotion just look all over the world what most race teams are using
only complaint i have is that damn cooper tube i already chewed up one but now i bolted it to the case and there is no way it can move back in to the ring gear
