I haven't seen one. Does Dana make them? I seen one for sale but, can't find any info sites on the powerlocks? Anyone? :trooper:

The powerlock is a big brother to the tracklock which is commonly used by DC in the Jeep line of vehicles. Both are limited slip units and the powerlock is a far more durable and long lasting traction aid of the two. I have run powerlocks in the front end of my TJ for several years. No, it is not a locker but it will perform almost as well under certain circumstances, especially in the front differential. Hope this helps.

I've got one in the front but the one in question for sale is for the rear 20. I guess the clutches have been removed and shims replaced. I haven't had mine apart so I can't really comment on if that works better. My front 30 powerlock has always worked fine.

They are pricy (over $400) Randys Ring and Pinion has them, so does reider racing. I called a dana distributer and he said dana didn't make one for my 44 with 4:56- but Randy's DID have one for that- It's not clear if dana makes them or not (!!??!!) RR&P said they don't, the dana distrib said they do.. (maybe they make the parts and farm out assembly-Precision gear was mentioned)

Heres an edited e-mail I got from someone about the power-lok (no permission- I hope he doesn't mind):

I live in Washington state and many of the old Jeeps up here are running
Powr-loks as they allow the tight turns required to slip between the trees.
Most of the newer rigs are running lockers, but the Powr-lok is still a
viable option and one that doesn't break or cause other parts to break. I
was looking for a used one that I could rebuild (low budget rig here) and
finally gave up and put a lock-right in the front. I'm running a narrowed GM
14-bolt in the rear and the cheapest locker available for it is a Detroit,
so that's what I put in it. I recommend the Detroit if you can live with the
handling characteristics, but if not, the Powr-lok is about the most durable
limited slip available that transfers a decent amount of torque.





>
> The Spicer Powr-lok has nothing in common with the Trac-lok except the
same
> manufacturer. The Powr-lok has 4 spider gears and the trac-lok has only 2,
> so there is a major strength advantage for the Powr-lok. You won't be able
> to hurt one easily.
>
> The difference in the way the two L/S's work is something like the
> following:
>
> Trac-lok. Steel clutch plates are forced together by a pair of Belleville
> springs. Belleville springs are basically washers that are deformed into a
> cup shape. Smashing the cup back to flat "compresses" the springs. They
are
> pretty strong, but have very limited travel. What that means is that as
the
> clutch plates wear a little bit, the Belleville springs lose their preload
> quickly and stop applying pressure to the clutch packs. The main force on
> the clutch pack is the Belleville spring, with some additional force
coming
> from the pitch angle of the spider gear/side gear teeth. The spider gear
> teeth are thick at the bottom and thin at the top. As more torque load is
> applied to the differential, the spider gears try to force the side gears
> away, and this adds pressure to the clutch pack which helps to transfer
more
> torque. That's why applying the brake lightly can help to engage a limited
> slip diff. These diffs are notoriously difficult to reassemble, because
the
> spider gears are under tension. Disassembly is easy though, because the
> clutch packs are almost always worn out.
>
> Powr-lok. The Powr-lok has a clutch pack under each side gear similar to a
> Trac-lok. But it uses a different kind of spring to apply the clutch
> preload. Unlike the Belleville spring, the (coil or "S" spring, can't
> remember which) has significantly more travel. The clutch pack can wear
> considerably and the spring can still apply a meaningful amount of
pressure.
> Also, instead of relying on the wedging effect of the spider/side gears to
> load the clutch packs, the Powr-lok uses a ramp under the end of the
spider
> gear pins to force the spider gears toward the side gears and apply
> additional load. These diffs are easy to take apart and put together.
> They're bolted together like most lockers. Different shims can be
installed
> to change the preload characteristics. Leaving a shim out can set one up
> with "zero-preload" which will make it undectible in the front axle on
snow
> and ice. Lightly applying the brake will ramp up the spider gear pins and
> allow it to transfer some torque. A thick preload shim or an extra one
will
> result in a lot of preload which will allow nearly zero differentiation.
>
> A Powr-lok is a great way to save the fragile u-joints in a weak front
end.
> It will transfer quite a bit of torque, but not so much as to break parts
> like a full locker.
>
>
> In my opinion, the Powr-lok is the cream of the L/S crop.

Cool.....thanks. But, do you believe that replacing the clutches with supposedly stronger shims is a way to go?