[fordem]

I came across an air locker by a company which I though was Australian, but turns out is Chinese - TRE - is this anything more than just another knockoff off the ARB air locker?

One difference I'm seeing is that they use two airlines, a 5mm for the airline to "power" the locker, and a smaller 4mm one to "return" oil from the solenoid exhaust to the locker, which I haven't seen in the ARB installation instructions.

[Gwagensteve]

Yes, they are a copy of the early style ARB.
I have no idea why there is a need to exhaust air back to the diff. The solenoid just vents to atmosphere. I wonder if it’s a response to gear oil odour in the vented air(?) - if so I don’t understand why that should be an issue unless the seals aren’t functioning and there is gear oil getting into the plunger.

*baseless rumour* apparently the side gears are sintered but I can’t confirm this.

I have disassembled both the old style “RD88” style locker that the patent had lapsed on (which is what the Chinese are copying) and the new style air locker and the new design is very elegant and has less moving parts. I don’t believe the price difference between the TRE locker and a real air locker justifies buying the copy.

[fordem]

Given where I am and the shipping costs, I'm not willing to take the risk on anything questionable, the first tip off I had that there was something questionable was that I could not find any sort of application chart on their website to say this model fits this vehicle (I was trying to download the installation manual to take a look at it), and on a hunch I selected the 209 from the list and the manual said it was for the second gen models and at that point I decided to ask.

I sourced a rear axle and stripped it to make measurements, the ring gear will have to be machined to clear the RD209, and so far I haven't found anyone local willing to do that, admittedly I haven't been as thorough as I could have been with that search, but machinists that I can trust to do a quality job aren't plentiful.

I've looked at the differences in the old & new designs, and agree that the newer style is much cleaner and on the surface looks stronger.

One of my concerns is that I have noticed that the RD209 is not readily available in the US (which is where I buy from), I'm not certain if this is simply a supply chain issue, or a sign that it has been discontinued, I've been trying to find replacement struts & shocks for a second gen, some suppliers say those have been discontinued, ARB themselves say they are on backorder with no eta. I've yet to ask ARB about the RD209 as that is a "back burner" project, the suspension revamp is current and the shocks & struts are the only missing pieces.

[Gwagensteve]

Forgive my ignorance but surely machining the air locker case is preferable to machining the ring gear- is that not possible?

[fordem]

Apparently you'd have to take too much off the locker body, possibly weakening it - the ring gear ID is 108mm and the locker OD is 118mm, what the guys in the US are doing is opening up the ring gear ID and taking 0.117 inch off of the back side to get the correct pinion mesh.

I'm following what is supposedly a proven approach rather than re-inventing the wheel - I also have my eyes open for good used front & rear diffs from a 96~98 first gen.

[sideways]

On one of mine the crownwheel flange wasn't machined concentric with the carrier bearings, it was so bad if you set the backlash on the low side it would lock up after a quarter turn.

FWIW they're the same as the new style ARBs, they have been since shortly after ARB came out with them. I've never seen the sintered gears like ARB showed in their vid, always machined. The new ARB style is superior to the early with the weak plastic squirrel cage but the new style means you have to be much more careful with the air line routing.

If you were going to run one I'd totally disassemble it and reassemble it, mine were quite dirty inside. Given where there prices are at these days I don't think they're worth the saving over the ARB.

[fordem]

Actually, once Steve confirmed the TRE was an ARB copy, I pretty much lost interest. The idea that the crownwheel flange could not be concentric is mind boggling.

[Polar_Bear]

I found a tre air locker installed in a 5.12 vit rear centre at my local pick a part, was a pretty good score for $99

it only has 1 x 5mm air line running to it, no oil gets vented through the solenoid exhaust. I didnt pay much attention to the ring gear... just slapped the centre in and its been fine ever since