I have decided to buy that tool, it is not that expensive and I can
always sell it after I am done with this truck, at a modest loss. Paid
$45 or so including shipping.

It is called differential preload wrench C-4164.

i

OK, I did not think about it. The reason for my decision to do it this
way is to not throw good money after bad, that is, if the truck will
need to be taken to a dealer, to not pay for bearings twice.

i

I suspect that if the bearings are bad, you'll never be sure the backlash
adjustment is right or that it will stay that way.
I'd go for the bearings first.

LLoyd

OK guys... My plan for now is as follows.

0. The noises that I have are of two distinct kinds, a whining noise
that appears when I ease the gas pedal, and grinding noise that I hear
at low speeds.

1. I received the adjuster lock tab replacement from the dealer.

2. I will take off the diff cover again, and will try to adjust the
adjuster lock to reduce backlash to spec, using a dial indicator to
measure backlash. I hope (and would like you to confirm) that I can do
it using a screwdriver through the access hole.

3. If I cannot get a screwdriver through the hole, I could pull the
axle, and make a tool that goes through the axle hole and turns the
adjuster. I would make it out of some materials, I have a welder. What
I will need to know is dimensions of the tool (ie where to place the
pins etc).

4. After I do that, I will drive around to verify that the whining
noise is gone. If not, I will take the truck to a dealer. I realize
that the grinding noise at low speeds may remain, could be due to
trashed bearings.

5. If the whining noise is gone, I will take the diff apart and
replace the bearings that may have caused the grinding noise. I am
not, yet, sure whether it is easy or not to put it back together
correctly.

Does this plan make sense?

i