Harrop elocker A13457 and Nitro 4.56 gears for Brian's 2008 Tacoma 8.4"
(36 BIG pics loading)
DEC 1 2017

Brian is local and dropped his 8.4 off to me. I had the Harrop/master kit/456 Nitro gears waiting on the bench.
To view the front 8" clam 456 gear install CLICK HERE.

The harrop elocker with the harness and Nitro gears.

Some kits have the generic seals and some have the upgraded Japanese seals and this one had the generic so a genuine oem seal will be substituted.
I'm holding up the wrong part number but you get the idea.

A quick resistance check shows 4 ohms of resistance....pass.

Applying 12 volts means about 3 amps is being drawn and the grey electromagnetic ring is magnetically bonded right now to the ramp ring.

Never ran across a burr or ridge on a Nitro yet....this one is just fine. So is the mating surface on the Harrop.


On the right can be seen the 2 washer plates that determine carrier bearing preloads and backlash values.
.111" on the left and the same .111" on the right....rarely are they the same.

It took an Earthquake to shake the 12 super tight and loctited factory ring bolts off.

The ring gear is pressed on using wood....and about 1 ton of persuasion.

Per the fsm, 92 ft/lb and blue Loctite.

This end is done.

Pressing the pinion out.

Old race was removed and the new Koyo race is going in.

Skipped a few pics but the new inner race was installed with a .087" pinion shim (behind the race).
New bearing was then pressed on the 456 pinion shaft.

Mount the pinion with the shop flange and mount the Harrop case and this is the resultant paint. Driveside....perhaps a touch too deep even for me.

Disassemble and remove .002" from the pinion shimpack. The .005" was removed and the .003" replaced it.

Removing the .002" is the "tweak"....I know I will be happy with the results so now I can put the solid collar in.

On the 3rd try, the collar shim was nailed down. The oem seal is now installed and the flange can be installed.

29/64" hole has been drilled.

Backlash is dialed in here.

Last chance to get the desired carrier bearing preload. My final CBPL measured 8 in/lb which is a solid, strong preload.

The stop tabs were adjusted and measured with 2.5mm of freeplay....the book says around 2mm.

The tabs were bent out slightly with a crescent wrench.

The FSM says 83 so that's what I use.

Backlash is checked on every other tooth and the backlash minimum here is .005"



The comet tail is right in the middle so it's me that I'm right at the slight deep condition which means quiet gears and max strength.

12 volts is hooked up and the locker works great.


Ready for Brian to pick it up.

A light engraving of the specs measured.

A snapshot of the assembly notes.