I've got an FJ80 High pinion diff with an ARB in it. It is new and has not been run yet. Someone else put it together.

I was inspecting the seal housing and adjuster nut on the air side of the carrier. The adjuster nut looks loose. The seal housing screws are tight and the locking tab (bearing cap) is in place. The seal housing and adjuster nut (and whatever else it is attached to) rotates slightly when you rotate the housing and ring gear.

Is this right?

NO

When the 3 alen head screws are tightened, the air ring is supposed to be locked to the bearing lock ring(flat, supplied with the arb"

Originally posted by GearMan
NO

Now that is what I call a straight answer:D :D

So this means that the adjuster nut on that side was not tightened properly, right? Any other reason it could be loose? Will I need to go through a complete backlash chech or can I just tighten it down? I think I understand back lash but I've never done it.

Crash: the allen screws are tight and the seal housing is locked to the bearing lock ring, they turn together as a unit.

i have run into where the supplied adjuster from ARB does not have a good fit in the carrier and it allows the adjuster to move up and down when the cap is all the way on. this will also cause it to turn like you describe. but first undo those little allen screws and take the adjuster lock off and see if you can tighten it up any more?if so then check to see if the adjuster moves up and down while the cap is on.if it doesnt and you can tighten it then after tightening it check backlash it shoul be no more then .010and no less then .005. GOODLUCK

OK, the adjusting nut seems to fit fine. There is no play in any direction except that it was loose. I was able to tighten it and it was barely loose. It only moved 1/8" and snugged right down. The locking tab will still fit in the same hole although it butts up against the side of the hole opposite the side that would keep it tight.

How tight should the adjusting nut be? Should I force it to the next hole? (my gut says no). Assuming the other sides adjusting nut is still locked, can the backlash change with this small a movement of the nut? I don't have a dial guage to actually check. Should I borrow one to be sure? Lastly (at least for now:D ), can I pivot the locking tab so it will hold the adjuster where it is?

Thanks for helping the gear work nubie :eek:

I made a tool so that I could tighten the adjusting nut properly and then I got it to move one full adjusting hole tighter. This made it good and snug without really cranking on it.

Should I put the lock tab back and run it or is checking the backlash again a must?

run it

Run it I shall

Thanks again :D :D :D