Tim Has Terrible Noises After a Local Gear Install
(55 BIG pics loading)
AUGUST 19 2016



Fins and Things Trail, Moab

Tim is somewhere in Missouri and emailed me about the results of a local gear install from a local shop.
After some email exchanges and a little while later, 2 strong boxes arrived.

The front 3rd member is in this box....
The actual front autopsy/rebuild can be followed here..... Front Inspection/rebuild

...and the really heavy rear 3rd is in the other. Both have ARBs.

This link is for the rear 3rd and it is shown secured to the fixture for a preliminary check-up.

Driveside....a pattern check shows that the pinion depth is extremely shallow.
No wonder it was making terrible noises. Good thing Tim only drove it a few miles.

Coast reflects that.

Backlash was terribly wide at .019".....The carrier and pinion bearings were not unusually loose.

Teardown begins. I verified the arb held air pressure before removing this stuff.

Both adjuster wheels seemed locked up.....could not break them loose.

Finally managed to get them off. The arb wheel has raised lip damage from hits with a hammer
and flat punch of some sort.

A flat surface and 100 grit sandpaper will fix the high spots like new again almost.

Some grooves in the arb journal. Still held air just fine but surprised to see so much wear.
Thought it was a newish arb.

There was rust/corrosion in both of the wheel threads and that is why they seemed locked up and would not turn.
A wire brush managed to clean them out like brand new almost. Shown above is after the brush was used
but before the debri was flushed out.

Verified they were all at 81 ft/lb minimum and they were.

Even the drive side of the pinion shows the extreme shallowness that the ring gear experienced.


Flange was removed....a small groove here.

The seal has some corner issues.....interesting.


Pushing the pinion out now.

All looks ok here....some streaking marks on the new rollers but that could be contamination in the gear oil too.

The races look a little more "used" or older but can't be 100% sure.

Removing the pinion bearing.....

....and NO pinion depth spacer found.

Going to try .0595" for the 1st pinion shim check.

Pressing it back on with the Harborfreight 12 ton.

Loadings up the pinion assembly into the diff carrier.

Notice how clean and spotless the 4 bolts are here? Guess I should have taken a "before pic"
because they were loaded up with carbon chunks and what appeared to be loctite.

The ring gear was now making full contact in this corner....guess that's why the shop had .019" backlash.

Nothing that 5 seconds with a flapper wheel couldn't fix in no time...
After this clearancing, the carrier would fit just fine and backlash could be set to spec.

1st real pattern check and now the pattern has nice placement from toe to heel
but it's a little too deep (face to flank) even for my tastes.

Coast. I know from past experience if I go down to .055 that it will be right where I want it.

Skipping some repetitive pics, the pinion shim was changed to .055" and a new crush sleeve is employed.
A new pinion seal is ready to go on.

Gear oil is lightly applied to the related surfaces.

The new sleeve was crushed until a light 8 in/lb was recorded.

DING!! and this end is complete.

The case is re-installed and a total preload check is made...good....right at 15 in/lb.
That means my carrier bearing preload is 15 - 8 = 7 in/lb.

That's what I like to see....a slight deep condition and very centered at that.

Coast....also very centered for good balance. Looks like a ufo.....proof that they do exist.

The drive on the pinion says perfect! This gearset will have maximum strength.


A final check on bearing cap torque.....70 ft/lb on all 4.

Backlash is recorded on every other tooth as shown in the notes at the end.

ARB seal housing assembly is in place and the retaining clip is installed as shown.

10+ ft/lb

Air check.....100 psi pass.




Final notes.

Boxing it up in the same double box.

Shielding the floor of the box with a conveniently sized Nitro box stuffed with packing materials inside.