Clam 8" gets Harrop elocker and cryo 456 Nitro thick gears on Mike's 07 4Runner
(115 BIG pics loading)
DEC 18 2016

Mike is in Sunny California and here
is his 07 4Runner with both diffs
removed awaiting 456 Nitro gears with
Harrop Elockers for both ends.

The lockers and gears are the start of Mike's build - beefier suspension, f&r bumpers, rack,
skidplates, sliders, bigger tires, etc have all been been ordered and a few have already
arrived. Nam, Paul and Mike should be finished with their builds for the
TLCA Moab event, in May.


Welding and flapper wheels.

This link is all about the front 8" clam.
There will be a hotlink down below a couple pictures for the actual rear 8" install.

The plan is to upgrade the tire size to 34".....4.56 Nitro gears will give back the acceleration.

Mike's gears were dropped off at Cryogenics International.
2 of them are Mike's...2 are Paul's...and the one loner to the side is from
a Dana 60 that someone dropped off while I was chatting with Charles.

Charle's has redundancy...more than 1 chamber. What if a chamber craps
out? Product is coming in and nothing seemingly would be going out. Are
the chambers real chambers or are they just revamped refrigerators? This
is one reason why it is so important to actually see the setup...seeing
that it really is computer controlled. Maybe having a large chamber and
a mini-chamber, like this one, to handle smaller loads.


Be assured that I have marked all 4 ring and pinions so that they stay as
matched pairs.

On the left is product received from
I emailed Mike about which Harrop elocker model to order for his gear ratio selection
and logic said it's the 110 model for ratios 3.91 and above. Logic is good when all
variables are known. More on that oversight later in the link and the easy solution.

Link for the rear 8" install..... REAR BUILD

On the right is the Harrop Elocker.
Contact Ward Harris (National importer/authorized dealer for Harrop) at 1-800-224-7801
or email

Nitro Gears are high performance gears. They set up well also. A solid spacer was included in the gear package.
Description says it includes "Side Shims" and those shims may or may not be of help in setting up the gears.
The best route is to get a complete set or at least a select set of oem washer plates. See below.

90564-50184 T=1.58, .0622" LH 1 $11.31
90564-50124 T=1.60, .0630" LH 1 $9.05
90564-50185 T=1.62, .0638" LH 1 $9.05
90564-50186 T=1.64, .0646" LH 1 $9.05
90564-50126 T=1.66, .0654" LH 1 $9.05
90564-50187 T=1.68, .0661" LH 1 $11.31
90564-50188 T=1.70, .0669" LH 1 $9.05
90564-50128 T=1.72, .0677" LH 1 $9.05
90564-50189 T=1.74, .0685" LH 1 $9.05
90564-50190 T=1.76, .0693" LH 1 $11.31
90564-50130 T=1.78, .0700" LH 1 $9.05
90564-50191 T=1.80, .0709" LH 1 $11.31
90564-50192 T=1.82, .0717" LH 1 $11.31
90564-50132 T=1.84, .0724" LH 1 $9.05
90564-50193 T=1.86, .0732" LH 1 $11.31
90564-50194 T=1.88, .0740" LH 1 $11.31
90564-50134 T=1.90, .0748" LH 1 $11.31
90564-50195 T=1.92, .0756" LH 1 $11.31
90564-50196 T=1.94, .0764" LH 1 $11.31
90564-50136 T=1.96, .0772" LH 1 $11.31
90564-50197 T=1.98, .0780" LH 1 $11.31
90564-50198 T=2.00, .0787" LH 1 $11.31
90564-50138 T=2.02, .0795" LH 1 $11.31
90564-50199 T=2.04, .0803" LH 1 $11.31
90564-50200 T=2.06, .0811" LH 1 $11.31
90564-50140 T=2.08, .0819" LH 1 $11.31
90564-50201 T=2.10, .0827" LH 1 $11.31
90564-50202 T=2.12, .0835" LH 1 $11.31
90564-50142 T=2.14, .0843" LH 1 $11.31
90564-50203 T=2.16, .0850" LH 1 $11.31
90564-50231 T=2.18, .0858" LH 1 $11.27
90564-50232 T=2.20, .0866" LH 1 $11.27
90564-50233 T=2.22, .0874" LH 1 $11.27
90564-50234 T=2.24, .0882" LH 1 $11.27
90564-50235 T=2.26, .0890" LH 1 $11.27
90564-50236 T=2.28, .0898" LH 1 $11.27
90564-50237 T=2.30, .0906" LH 1 $11.27

90564-50224 T=1.44, .0567" RH 1 $9.05
90564-50225 T=1.46, .0575" RH 1 $9.05
90564-50226 T=1.48, .0583" RH 1 $9.05
90564-50227 T=1.50, .0591" RH 1 $9.05
90564-50228 T=1.52, .0598" RH 1 $9.05
90564-50229 T=1.54, .0606" RH 1 $9.05
90564-50230 T=1.56, .0614" RH 1 $9.05
90564-50204 T=1.58, .0622" RH 1 $9.05
90564-50154 T=1.60, .0630" RH 1 $9.05
90564-50205 T=1.62, .0638" RH 1 $9.05
90564-50206 T=1.64, .0646" RH 1 $9.05
90564-50156 T=1.66, .0654" RH 1 $9.05
90564-50207 T=1.68, .0661" RH 1 $9.05
90564-50208 T=1.70, .0669" RH 1 $9.05
90564-50158 T=1.72, .0677" RH 1 $9.05
90564-50209 T=1.74, .0685" RH 1 $9.05
90564-50210 T=1.76, .0693" RH 1 $9.05
90564-50160 T=1.78, .0700" RH 1 $9.05
90564-50211 T=1.80, .0709" RH 1 $11.31
90564-50212 T=1.82, .0717" RH 1 $9.05
90564-50162 T=1.84, .0724" RH 1 $9.05
90564-50213 T=1.86, .0732" RH 1 $9.05
90564-50214 T=1.88, .0740" RH 1 $11.31
90564-50164 T=1.90, .0748" RH 1 $9.05
90564-50215 T=1.92, .0756" RH 1 $11.31
90564-50216 T=1.94, .0764" RH 1 $11.31
90564-50166 T=1.96, .0772" RH 1 $9.05
90564-50217 T=1.98, .0780" RH 1 $11.31
90564-50218 T=2.00, .0787" RH 1 $11.31
90564-50168 T=2.02, .0795" RH 1 $9.05
90564-50219 T=2.04, .0803" RH 1 $11.31
90564-50220 T=2.06, .0811" RH 1 $11.31
90564-50170 T=2.08, .0819" RH 1 $11.31
90564-50221 T=2.10, .0827" RH 1 $11.31
90564-50222 T=2.12, .0835" RH 1 $11.31
90564-50172 T=2.14, .0843" RH 1 $11.31
90564-50223 T=2.16, .0850" RH 1 $11.31


Genuine KOYO bearings.


The electromagnet assembly is left to the installer to final assemble....and it really is easy to assemble.



3 pins plus assembly.



Pretty straight forward how it goes together.

Leave this to the side for the moment.

Time now to dis-assemble the clam. Remove the ten 14mm bolts and the cover pops right off....
with numerous tap taps.

RTV was cleaned off with a hi-speed wire brush.

Pinion is pressed out.

The factory flange and the expensive flange ring gear bolts will be re-used. No after-market
replacement flange is available....has to be from the dealer if a new one was needed.

The electro magnet is placed in the bowl to see the clearancing that would be needed. And, I can see,
that the tab is at the 12 o'clock position and that the hole that will be drilled for the rubber
grommet will be very near the 6 o'clock.

Looking at the area that that will see the dremel.....

I have this attachment kit for my dremel but the exact tip that I desired was actually purchased separately.

The good book shows the 3 spots that need touch up.

This is the preferred tip for this kind of work.

Material came off quickly.


All done. Probably best to test fit the electromagnet several times before final pressing onto the Harrop carrier.

Insert the 3 pins....rounded end up.


Ramp plate then bearing thrust washer.

Electromagnet is next. That's a wet looking special epoxy they used for sure.

Tab is TIG welded on. Be nice to have my own TIG machine at times.....

Then the bearing race goes on.

And finally the bearing spacer drops in place.

There's a small step in the journal so the last 1/10 of an inch is a tighter fit. I wouldn't call it
a tight press fit but tight enough to keep it all in place while the carrier bearing presses in place.

Find that "just right" widget.....

............. press it lazy finger will do the trick. Light taps from a hammer instead of a press would work too.


Surfaces checked out just burrs or high spots noted. Holding off putting the ring on
because the tab and the electromagnet should be double checked to clear things.

Pressing on this one carrier bearing....

....and use it to test fit it....

With the ring gear off it's possible to see how it clears. Just a tad of contact I could see and feel.

A little more clearancing with this.

Now it should clear.

I ground in about this far here....

....and this far here.

Looks good.

I can lightly turn it back and forth and can hear the tab tapping the ribs like it should.
Has a good feel and can tell it's not rubbing anything.

Now the other carrier bearing can be pressed on. The ring gear is now inserted and tightened down to
86 ft/lb per the fsm. Blue locktite also.

New pinion races are pressed or tapped in place.


New bearing and the original .076" pinion shim are pressed onto the 456 pinion.

Once the pinion was mounted in the clam housing it was quickly realized that these THICK 456 gears and the
#110 elocker don't play together. The solution is to use the #994 harrop elocker and this
allows the thick 456 gears to be positioned perfectly.
Nitro supplies the 456 ratio only as thick normal thin ones. I'm sure they do this to allow
customers to re-use their stock 373 carriers and be able to fit 456 gears without the expense of buying
another offset stock oem carrier..

So the ring is moved over to the loctite and 86 ft/lb.

New carrier bearings are pressed on.

We've kept the original races in for the test fitting and now it's time to press new ones in.

New one is pressed in. This is repeated for the other carrier bearing also.

Few little steps skipped but the lid is put in place and a backlash check is made.

With my fixturing in place, a painted pattern check is also made.....

Too deep with .076".

Coast seems to agree too.

Teardown and push the pinion out.

This bearing separator is the perfect tool to remove the inner pinion bearing. I don't know how many
thousands of times this has been used for this exact same operation in the last 10 years. The 2 main halves
of this bearing separator were cryo treated back in Nov of '07 and still going strong.

Reducing the pinion depth to 072.


Pinion mounted up(no crush or seal at this point).

Elocker dropped in place and lid bolted down....

Same fixturing and apply some resistance to the rag while turning the ring assembly.

DRIVE----Much better, good depth

Coast----looks right on.

drive reverse painted.

Coast reverse painted.

With depth established, now the solid collar can be set.

After 3 tries the solid collar is good. Now is the perfect time to drill the hole for the grommet.
Almost exactly opposite the tab location. Steel ruler is showing the dimple where the hole is to be drilled.

Pilot drill first.


Suck up 100% of the drill filings.

Position of the new hole is here...

2.25" from the top lip.

Final drilled to 29/64" (.453").

Very thin housings on these clams. Only about .125 maybe .140" thick. The rubber grommet might not
seal properly and leak some gear oil.

Rubberized seal is now mounted.

.165" below the deck per the fsm.

The factory flange with a new flange style nut is threaded on....and anti-seize was also used.

Pinion nut is tightened to over 220 ft/lb at which point I noted 10 in/lb PPL.

Other side has a zero gap...this side has .013" gap. That's an average of about .006"

With the 10 lid bolts tightened to 51 ft/lb, I was noting 22 in/lb total preload.

A double check of the backlash on 7 places around the ring gear yields .007"

The cap is removed one last time for the factory recommended FIPG (00295-00103).

51 ft/lb.

Best to let set 24 hours before adding gear oil.

A proper sized nut was migged and the final drill hole was .465" as it was nearly impossible to pass
the grommet thru a .453" hole even gooped up with FIPG. This grommet is leak free.

The clam will go back in the exact same dual box that Mike sent it in as this one still has a lot
of good miles left in it. I get this feeling that I will see this box again when Paul gets ready
to send his diffs to me in a couple weeks.

A couple functional checks that I do on the elockers.....check the resistance. 4.8 ohms here.

Amps drawn from a 12.4 volt battery.....3.03 amps.

Final notes of the install.

Securing the clam and bubble wrapping the misc. harness parts.