Hi morrisdl, I have just been directed to this site and in particular this posting, by a member on my normal D3 site DISCO3.co.uk. as I'm due to overhaul my rear diff and am seeking any info I can get on it.

The data on the Backlash and preload figures is great to finally find out, but do you happen to know where the backlash measurement was taken. On most other diffs backlash is measure at the heel of the teeth on the ring gear, but here access is to the gear is not possible when it's back in the case as your 2nd photo shows.

As I will be reusing the pinion and ring gears (assuming they are not worn) I hope that there will be no need to do any extensive checks and adjustments, but I will non-the-less check backlash just to be sure it is within tolerance. Thanks for any more info you can impart.

 

Great question about the Backlash check. I have only done ARB installs on my 101 salisbury axles, but for those I could just pull the diff cover. Here is the only theory I have for the LR3. On your old unit you could attach something to the pinion flange, say bolting a 12" ruler so that 2-3" are covering the flange and the other 9" are off to one side, and then measure how far the ruler is moving at its end as you rotate the flange. Assuming your current diff is within spec, if you replicate this exact measurement on the rebuild then that should translate to the same backlash spec. Disclaimer: I have never heard of that being done or done it myself, but it's theoretically plausible.

 

Sorry Alpha, I do not know and Im not sure I would even understand if my tech told me.

 

Here is a photo from a GM differential. Here is the general idea for measuring backlash from outside the diff. These GM instructions called for multiplying the measurement you took from the yoke by .5 to read the real measurement. However without knowing any ratios associated to the LR3 diff, I can't suggest anything beyond matching the measurement taken before rebuild

 

The problem with taking pre-strip backlash measurement is that they could be way out depending on the ware in the diff. so comparing before and after is out.

Your suggestion about taking the external measurement seem reasonable, but would need to know the limits to apply and at how far out from the centre of the pinion gear shaft. Maybe, as been suggested by another poster elsewhere, bolt ruler or such to the yoke and take measurements at a point equal to the crown gear radius.

When I start I will be getting advice from a reliable source.

 

I wonder if you could tap into the EAS reservoir as the air source... It stays at a constant pressure anyway.

 

You could, but Im not sure its a good idea. I like the simplicity in theory, but the suspension compressor is too fidgitity enough already. I tried to source all the fittings, but it was was not simple since the LR compressor is metric and the ARB stuff is SAE. The regulator, shutoff valve, and actuator were all going to push the price very close to a dedicated ARB compressor if not more expensive. If it was possible to run the ARB as a backup to the EAS compressor that might be worth doing.

 

That's exactly what I have done. I installed a front locker ARB in my rig, and I just plumbed it into my air reservoir. The conversion fitting to switch between SAE and metric wasn't very expensive. I believe I got it from a website called discount hydraulic. I also ordered a shut off valve a regulator and a pressure relief valve and then plumbed plastic airline between everything. All of these thing you are going to want regardless of where you are getting your air. The only issue I ran into is that my skid plate mount interferes with the conversion fitting and I had to notch the mount for clearance

 

Wow Volkov so you have a front locker...and can I assume you have the rear locker as well? I'd be really interested to see what kind of terrain you can conquer with the front locked that having the rear locker+4ETC couldn't get you through.

 

I am running BF Goodrich all terrain tires, I needed the highway manners, so that does reduce my off road ability some. But from what I have seen on the trails with other LR3s I don't have any wheel slip and I don't require as much momentum, but they have all done what I have done. I guess it is kind of like the difference between the non HD rovers and HD rovers.