POW!!! went the 529 in the Front Hi-pinion ARB 3rd
(31 low res pics loading)
DEC 2 2006

Tim is local to me and recently took his gears out on this exact obstacle.....the fronts were in a tight bind and even with some common sense use of the clutch, the gears went bye-bye. Tim is not running a gear eater....It's an 85 X-cab pickup 22RE 5 speed with a single 4.7 case and 36" Iroks. The 3rd was purchased about 18 months ago from a national 4x4 chain pre-assembed and ready to go. With Tim's modest use of the clutch and his drivetrain set-up, this should have lasted much longer. First, to do an autopsy of sorts and then install some heat treated and cryo'd 529 gears from Bobby Longfield.

The main damage to the ring...


The pinion teeth are stronger and the teeth usually stay intact.

This is most of the debris found in the oil.

Strange that the o-ring blew out. Tim reports that the ARB worked perfectly up to the very end.

The special ARB adjuster wheel was tightened with the wrong tool....the chisel and hammer method is a no-no with this adjuster. The raised ridges causes the seal housing to sit un-evenly and could cause an o-ring to pop out.

Strangely enough, the commercial 3rd did not have an oil retainer...no oil slinger....and came with just a cheap crush sleeve. This new install will have the right stuff as shown above.

Upon dis-assembly, I noticed that one of the adjuster wheels was not installed properly and most of the damage was restricted to the wheel itself.

This is the new Bobby Long ring and pinion along with the new seal housing assembly and improved Viton o-rings.

The heat treatment is obvious looking at the blue discolorations.

The ring is pressed on the ARB case. ARB seems to run tight tolerances and the tight fit is typical.

As usual, red loctite and 75 ft/lb on the 10 ring bolts.

Both cryo treated carrier bearings were pressed on.

A .079 pinion shim is pressed on with the cryo bearing.

The oil retainer taps into place very nicely right under the outer pinion bearing race.

Both pinion races are pressed in place at the same time.

ARB cases are just a little bigger than other cases so they are known to occasionally contact the pinion teeth. I am being pro-active here and will use the flapper wheel to soften the edges and improve the clearance. This does not effect strength.



The solid collar is left out until I get the pinion depth set correctly. The pinion nut is tightened until about 10 in/lb of pinion drag is measured.

too deep.

heavy heel pattern...

Teardown and remove the bearing and lighten the shim....

Seems ok....but maybe I could go a little deeper now.


Re-shimmed to 071 and I like this much better.

The coast side is not as "classical". Backlash changes did not help.

With the correct depth, now is the time to install the solid collar and get the shim value right for it. On the 4th try, I had a shim of .024" and 10 in/lb of pre-load.

Tim works on trimming the ARB copper tubing here.

The carrier bearing adjusters were carefully tightened to get the 150 pound pre-load.

Just have to ding the pinion nut and done :)