I bought my 2001 Taco just a few months ago in the summer of 2006...it had 72k miles originally and now has almost 80k. Time to "re-fresh" the carrier bearing pre-load (CBPL). Just through normal wear the bearings have loosened up. Tightening up the CBPL will greatly reduce ring gear deflections resulting in maximum gear strength. This becomes a big deal when I have to pull my buddies out of a mudpit or something.
There are many older Toyota trucks out there that have 150k miles or more on the rear diffs. This procedure here works just as well for them, too.
Additional note 7-19-2009----High mileage bearings might not appreciate high pre-load values. Sometimes, it's a difficult call by just looking at a used bearing if it truly is approaching self-destruction. As might be imagined, if the carrier bearing pre-load is bumped up quite a bit then that self-destruction could occur quicker. That being said, my bearings are 6 years old and I decided to tighten them "a good amount" as shown below. I think it goes to show that the factory is running the bearings with a very light pre-load.

Another note 8-7-2011----In this link, I tightened both sides exactly 5 notches each. What I could have done was perhaps tighten the case side 5 notches and the ring gear side 6 notches. Why an extra notch on the side closest to the ring? Because the ringside bearing sees more strain and wear so give it the extra notch to keep the same approximate backlash value as started with. I didn't do this to mine.....but it's a good practice nevertheless.

First, drain the gear oil...that's my salad bowl but I don't eat that many salads anyway.

I chose to use a floor jack and 2 jack-stands to get the wheels off the ground.

I removed the emergency brake cable...the drum...the 4 nuts on the backing plate...the hydraulic brake line connection and then the axle itself. Repeat on the other side. My shoes looked like new. No rust at all. Gotta love Arizona. :)

I dis-connected these 3 items on the top of my E-Locker...

I tied the driveshaft up out of the way.

Remove the eleven 12mm nuts and remove the carrier.

I removed the motor guard and noticed the 5 wires were compressed...anybody that has E-Locker issues should remove this cover and see if these wires have rubbed through, possibly causing a short.

Oh ya....the E-Locker might not come out of the housing unless the locking fork shown here is in the LOCKED position (fork to the inside).

Not necessary but I chose to record the backlash. I measured 7 thou.

Remove the 12mm locking tab bolts.

I made up a tool to effectively tighten the spanner adjusting rings. I was able to get 5 notches in tightness. I tightened it to about 100 ft/lbs torque....100 foot/pounds on the wheel adjuster is about 10 INCH/POUNDS on the carrier bearings themselves.

The other side was tightened the exact same 5 notches. 5 Notches on each side sure seems like a lot. I now have some confidence that I can strain the hell out of this rear diff and it will survive. :)
Now just clean and re-assemble everything in the reverse order and done!
Update 7-19-2009---I've put 30,000 miles on it since tightening the bearings, mostly road miles, and all is well so far.

UPDATE....JAN 7 2011.....another 20k miles on the truck since the last update and the rear 3rd is still performing perfect. The carrier bearings are not causing any problems.

UPDATE....FEB 11 2016.....another 55k miles on the truck since the last update and the rear 3rd is still performing perfect. New G2 488 Ring/pinion on this go-around but still running the same original 4 bearings from the factory!

Oh ya....if the pinion is loose then that needs to be addressed also...but that's a whole new link..... and more difficult, also.
Happy wheeling. ZUK