Richmond Powertrax for the Ford Explorer 8.8 axle
Richmond Powertrax Locker Review
by Bill Plein
March 5, 2006
In our continuing buildup of a "grocery getter" 1997 Ford Explorer into a
competent trail rig, we are seeking more traction. In the first part of the
upgrade, we added a
Superlift 4" lift to get us up and over the obstacles, but found out that
we'd get stuck when we lifted a tire. The obvious next upgrade is some sort of
We have choices when it comes to adding traction to a stock SUV.
- Limited Slip (factory or aftermarket)
- Automatic Lockers
- Selectable Lockers
Anyone who does any wheeling will tell you that limited slip is "limited" in
terms of how much it will help you off-road. I can validate that, my Explorer
would lift a tire and spin when crossing over deep ditches at an angle. Luckily
for me, support for the Ford 8.8 is plentiful for both automatic and
selectable lockers. This truck is a daily driver, with both my wife and
myself driving it weekly, and I wanted something simple, reliable, and always
there. While selectable lockers have their place, the added complexity of wiring
made it a second choice, with automatic lockers rising to the top of the list.
There are a few downsides to automatic lockers:
- Always-on means that you will get a little more
squirrelly in icy/slippery
road conditions, correctable with alert driving
- Automatic lockers tend to be noisy around turns, as their mechanisms for
locking click or bang when engaging/disengaging to allow differentiation.
Given all the above facts and tidbits, I decided on the Richmond Gear
Powertrax. The Powertrax has a unique design that limits the noise, and gives it
a much more streetable personality than some more intense lockers. In addition,
Powertrax is one of the few models out there that has a specific application for
a Ford 8.8 with Limited Slip. Most lockers only support the non-L/S carrier,
necessitating a carrier swap which increases the cost and complexity of the
upgrade. Remember, we're building a daily driver that can also hit the trails,
not a hard core rock crawler, so we need to be concerned with budget.
Finally, the Richmond Powertrax has a reputation for ease of installation. I'm not a
daily wrench monkey, and I figured that if I can do it, so can thousands of other Explorer owners.
The Powertrax comes in a handsome box with a clear and legible installation
guide and user manual:
Note: I found the user manual to be VERY detailed, and
absolutely valuable in this process. Keep it handy, and follow it closely. There
are details in the installation manual that aren't found in this review!
I was having some problems with my existing axle (pinion gear whine), so I
sourced a used axle in really good shape, cleaned it up, hit'er with the
rattlecan and threw it on a stand for upgrading before putting it under the
vehicle. Here we see it draining, the oil was very clean and the magnetic drain
plug had almost nothing on it. This was a well maintained rear end from a fleet
vehicle with highway miles.
First order of business is to remove the pinion shaft: First, remove the
retaining pin. It will be torqued on pretty tight, so you'll have to prevent the
carrier from turning by using a dowel or other tool to wedge the carrier in
place. This is a 5/16" head on the retaining pin, so we're not talking about
having to use a breaker bar here!
The pinion shaft will be firmly caught inside the carrier, best bet is to
turn the carrier until this side shown above (the side with the retainer pin) is
facing away, and then lightly tap the pinion shaft out an inch or so, enough to
turn it back around and grab it, but not enough to pound it into the back of
your differential housing and really get stuck! Then simply push the axles
in in order to expose and remove the C-Clips. Note: If you drop a C-Clip with
your axle up on a stand like this, it will fall down and get lost in the back of
the diff case, necessitating you rescue it immediately!. If you are doing this
with the axle on it's side, such as under a vehicle, that's a near
With the C-Clips removed, slide your axles out about 8" per the instruction
manual, and remove the clutch spring. The clutch spring is in there pretty
tough, in my case we tapped it out part way (into the housing), then turned the
carrier 180 degrees and pulled it out.
The next step of the instruction manual tells you to remove the spider gears
and their thrust washers. But how! Well, if you think about it, the spider gears
are held in place by the pinion shaft, and with that gone, just turn one axle
(re-insert it first!), and the spider gears will walk out by themselves. In my
case, the thrust washers were stuck to the spider gears, so no small parts to
fall back into the diff case. Then, with those out, just pull out the side
gears, clutches and thrust washers
Old limited slip internals out, new parts ready for installation! A little
bit of locker terminology: The top two pieces on the left are the couplers. They
are the outermost portion of the locker, splined to couple with the axles. They
have teeth that engage with the drivers, which are shown just below the couplers. The drivers install
in the center between the couplers. They are driven by the pinion shaft. To
allow differentiation, the teeth between the coupler and the driver will
disengage, yet stay engaged when necessary for locking. In the center of
each driver is the spacer.
After verifying that the gaps in the coupler are aligned with the synchro
ring (see Powertrax install guide for details), you grease up the driver teeth
and the spacers, and use grease to hold in 4 saddle springs per driver:
Now you install the couplers into the carrier, ring-side first, then install the
C-Clip on that side.
Next, install the coupler on the passenger (non-ring) side.
Then install a C-Clip on the RING SIDE ONLY! After C-Clip installation, you
want to make sure that the widest gap in the coupler teeth (the "paddle
opening") is facing UP. It will align with the paddle on the spacer which you've
previously inserted into the driver.
Next, insert the non-slotted driver over the ring-side couple. Align the
paddle with the gap in the coupler. Note that this photo shows the lugs in
the driver facing up, when following the manual they will be at the bottom.
Why is that necessary? In order to drop the passenger-side driver in, you must
drop it in lug-first, see the second and third picture below:
Note!!: We got stuck by leaving in one thin thrust washer on the ring-side. We
all looked at it and said "nope, it's clear", but there was one thin washer left
on the carrier surface, stuck there by gear oil. We couldn't get the locker
installed with it there, that's how fine a tolerance Richmond uses, and that's a
GOOD THING. After struggling with the installation of the locker drivers between
the couplers, we pulled them out, found the extra thrust washer, pulled it and
everything went together.
The drivers come in slotted and non-slotted form. The slot allows for
insertion of the C-Clip at the end of the process. After the hassle with the
washer noted above, I rushed everything together and had the slotted driver on
the wrong side. The following pictures illustrate that. When I got to the point
where I had to insert the C-Clip, I said "Doh!" in my best Homer Simpson
impression. Luckily, after you've gotten this far, it really is just 5 minutes
to take it all out, swap the drivers, double check your paddle/gap alignment,
and put it back together.
Here I am pointing out the spring slots in the drivers, you can see the slot
just in the upper (ring-side) driver. It should be on the other side! Doh!
The springs are doubled up, a light weight inner spring to keep the system
under mild compression, and a heavier duty outer spring to handle the loads. Put
the inner spring inside the outer spring, and insert into the slot. Don't let it
loose to fall into the diff case! When installed, turn 180 degrees and
Check the clearances with the "check block" supplied with the locker. It
should slip between the drivers when inserted along it's narrow edge, but block
if inserted across it's width.
You're in the home stretch! Insert the C-Clip through the slot (note,
the above pictures have the slot on the WRONG SIDE. Follow the manual, it is
very clear!). After inserting the C-Clip, you will want to feel through the
pinion shaft opening to make sure that all 8 saddle springs are still in their
slots in the driver. I had one fall out on me, we retrieved it with a magnet,
and reinserted it with more grease to make sure it stayed put.
Insert the pinion shaft, and fix it in place with the pinion shaft retaining
The manual describes a function test to make sure it's all
working. Make sure to run through the steps before sealing everything up.
Once you have passed the function test, clean up your old RTV on the diff cover and differential case, apply new
RTV and seal her up!
Road Test and Driving Impressions
Powertrax is really one of the more quiet, streetable
lockers out there. There is no ratcheting sound noticeable around turns,
although if you apply power in a tight turn you will feel it engage.
Occasionally (usually during power-on/off maneuvers while turning, such as
parking lot driving) you will hear it "clunk" into engagement. Like all
automatic lockers, power-on while turning at an intersection is going to lead to
a little bit of tire slip or chirp. If you are a young guy, the police
might think you are trying to show off, so keep the throttle down and you'll be
On the highway, the average driver won't even know it's
back there. I drove the vehicle up to Tahoe a week after installation, and it
was working perfectly. If you are a very astute driver, one who understands what
trailing throttle oversteer is and who knows how to subtly steer a car with the
throttle on an offramp, you WILL notice that there is a locker back there. If
you are driving, for example, on a freeway speed turn, application of moderate
throttle will tend to "push" the truck to the outside, due to the fact that both
rear tires are pushing at a constant speed, forcing the truck in a more
"straight" line of travel. Back off the throttle quickly, and the locker
disconnects and the nose will edge in. These tendencies are subtle, most people
will notice that something is "different" but nothing is going to surprise
I haven't had the truck out to the trails yet, but quick
tests on ice, snow, and mud around Tahoe showed me how much more traction was
possible with a locker. One complaint of lockers is that on hard pack snow or
ice, the rear end can come around because both rear tires will "light up". With
the automatic 4WD on the Explorer, as soon as this condition exists, torque is
transferred to the front axle, resulting in immediate traction at 3 of the 4
tires. Despite my disdain for automatic 4WD, this setup is very cool for driving
on the road in slippery conditions.
I have nothing but the highest recommendation for the
Richmond Powertrax. If you want to find a dealer, download manuals, or just find
out more info about the Powertrax by Richmond, check out their website at
The Differential Cover
During the planning for this review, we contacted Blue Torch to see what applications
they had for diff covers, and found out about their Kryptonite line of
differential protection. We didn't have it in time to include in the
installation that day, but I got it shortly thereafter.
I say "protection" instead of covers, because that's what
this product is. It's protection against the rocks. The Kryptonite diff covers
for the Ford 8.8" rear end is fabbed from 1/4" steel plate with a 3/8" steel
ring for the base. Considering that the truck we're putting it on is a dual
purpose, daily driver and sometimes trail rig, this is overkill protection! If
it's good enough for a rock crawler, it's good enough for my SUV. It IS
worth it, though. Think about the money you drop into your ring and pinion, or
your locker. How would you like to destroy those parts by dropping your diff
onto a ledge? Or peeling the stock sheet metal cover off and dropping gear oil
all over the trail, leaving you stranded? At under $140, this is cheap
The BTF Kryptonite cover is beautiful to behold,
especially if you are a gearhead! BTF laser cuts the plate steel, then folds and
welds it into shape. Each diff cover comes unpainted, and includes new
12-point bolts and washers for installation. In the pictures below, from left to
right, we see the inside, the welding detail, and the overall exterior. The unit
is shipped with a thin coat of oil on it for rust protection, which picks up a
bit of lint in shipment, but that's no big deal.
After cleaning the cover with brake cleaner, I hit it with
some 80 grit sandpaper in order rough up the surface for paint adhesion. I then
painted it with a gray hammertone paint, which contrasted nicely with the black
hammertone that I used on the axle. After letting that cure for a few days, on
You'll notice the shine of the unpainted differential
housing where the BTF Kryptonite cover isn't covering metal. I'll shape that up
with some rattlecan later, but it's nice to know that I don't have a 3/8" steel
lip down there to catch on rocks!
Looking for a cover for your application? See the
Blue Torch Fabworks' web site, they
have just about everything.
Vendor Contact Info
1208 Old Norris Road
P.O. Box 238
Liberty SC 29657
Blue Torch Fabworks, Inc.
P.O. Box 8367
Dothan, AL 36304