[1973Guppie]

so I am putting together a list of spares and think I have covered most stuff but had a question pertaining to arb air locker differentials. From what I have heard the actual ARB diff is fairly stout and you don't have to worry about breaking it. I have heard usually if you break (wheel hop), it will be a pinion or a ring gear. I am trying to figure out if I would be able to take apart a 3rd member on the trail and swap out the pinion and ring gear? I was going to carry a full stock 3rd member but weight and the fact that I don't have another sitting around made me think about just carrying a stock spare pinion and ring gear. Besides the ARB SST tool to pull the 3rd, what else would I need to replace the ring gear and pinion on a 3rd member in an emergency? I am thinking with a pinion seal, stt, pinion, ring gear and air tools it can be done no prob. Can this be done in the field? I know the gear mesh may not be perfect but in this case it would be to just get the truck off of the trail. Excuse my ignorance as I did not install the ARB's and they were done many years ago.

am I just better off carrying a full spare 3rd member??

Just trying to prepare better for the trail in the future. Hope you all don't think I am crazy.

Noah

[Mr. Notorious]

In my opinion I think it would just be easier to carry an open differential. By the time you bring all the right tools to do the job, you'll be close to the weight of the thrid. Plus without a spanning wrench or impact gun, I think it would be difficult to remove the ring gear bolts or even the pinion nut. Then after your spend the time to put it together on the trail, who know how long it will last on your way home with an improper gear mesh. Finally when you get home you're going to have to tear it all apart and rebuild it again properly. Seems like alot of extra work...

[too tall]

I'd carry a spare third and weld it up if you break an ARB then you're probably in some heavy terrain and you'll probably need the locked third to get out.

[Pin_Head]

Carrying a spare pinion for emergency trail repairs is not a bad idea. It may take a little more effort than swapping an entire differential, and the preload and tooth pattern probably won't be correct, but it will get you home. It is a lot lighter and smaller than carrying a spare third member.

[1973Guppie]

Thanks Pinhead, I will have air tools and an impact gun cuz I have a Co2 bottle, so basically to do this on the trail I would need to carry:

- impact gun
- pinion
- pinion seal
- arb tool
- used pinion bearings, washers, etc

* Also, is a 1973 stock 4.11 pinion fine spline or coarse spline??

Noah

[Pin_Head]

You probably won't need all that to just change a pinion. I would take a handfull of the ajdusting shims so that you can approximate the preload. Just get it so that it isn't tight after you torque the pinion nut down with a minimal amount of slop. You can also eyeball the ring gear backlash or (better) mark the position of the side bearing adjuster nuts to get it back the way it was.

Pinions are coarse spline from 58-77.

[1973Guppie]

sweet, so you don't need the arb tool to pull the diff, correct? just unbolt the side caps and it should drop out, just like stock? I think I will get a new pinion seal and stake nut to have on hand for good measure, thanks pinhead...

Noah

[theo]

I think you will also need some way to hold the pinion while you loosen and tighten the pinion nut. And a breaker bar for when your CO2 bottle runs out.

[1973Guppie]

yes, good point, I made a tool for this, need to throw it in the box....

Noah

[grant5127]

Originally Posted by 1973Guppie

sweet, so you don't need the arb tool to pull the diff, correct? just unbolt the side caps and it should drop out, just like stock?

gotta get the axles out first.....for that you will need the tool....