Toyota Tech

Toyota Tech: Regearing the Land Cruiser Electric Locker

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By: Mark Griese and Zuk - April 2006

Once I made the decision to swap a solid front axle onto my 2001 Tacoma, I knew I wanted a selectable locker. I've been running an ARB air locker in the IFS front axle for three years without a single strength or reliability issue. But for this project I wanted something with a little more 'yota in it. I chose the high pinion electric locker from the front of a full size FZJ80 Land Cruiser. After checking the classified listings on various message boards I found I could buy a new unit for roughly 30% more than a used one. Unfortunately these came from the factory with 4.10 ratio gears, and that just wouldn't be adequate for the tire size I expect to run after the axle swap. Since I was already running 4.88 gears in the rear, I decided to use the same ratio for the front diff rather than changing the rear also. I'm very happy with the driveability I have with the current tires and gears, so only time will tell if the smarter decision would have been to go with a 5.29 ratio!

When I asked around to find out who could install the ring and pinion for me, two people recommended Ken "Zuk" Francisco just from his reputation, even though neither one had their gears set up by him. I took a look at the write-ups on his website and could see that he has done many installs, learned some handy tricks of the trade, and understands the process very well. It's interesting that Zuk does this as a part time/side business, yet recently in the span of one week, he had five differentials to setup. That sounds like a bit more than part time to me!

Here are some great pictures and text provided by Zuk showing helpful tips on how to setup gears in the high pinion electric locker. I have modified what Zuk provided only to the extent necessary to fit our format on 4x4Wire. I hope you find the photos and text both interesting and helpful.

Parts for the install

Fresh out of the box To be installed....4.88 Yukon gears HP 4.10 E-Locker part number Yukon part number


The 3rd... loaded on the bench ready to be worked on Excellent pattern from the side. Nice coast. Start by removing bearing caps... Lay out everything in an organized fashion.

The factory flange and threads are larger than the after-market version. The pinion nut poses no problem for a good electric impact. Remove the very snug fitting flange. The hydraulic 10 ton press is so handy...even to push the pinion out softly. The light duty crush sleeve will be replaced with a solid collar.

Without the right tools, saving this bearing is not likely... ...unless something like this custom made "clam" is used. This is a bearing specific clam. Others require their own unique clam. Some light clamping pressure and the press will easily push the pinion out. The factory .079" pinion shim will be re-used on the new 4.88 pinion. Micrometers are a very important tool in gear set-ups.


The pinion bearing has been pressed on the new pinion. A collar shim value of .024" will be tried first. With the pinion secured in place, an inch/pound torque wrench will accurately measure the pre-load. Now it's time to load the ring gear up. Surfaces are checked with a file and cleaned. The ring gear took a very light pressure from the press to push it in position. Red Loctite will be used on the ring gear bolts. The steel tabs are in the garbage.

The case has been loaded into the differential carrier and the backlash and carrier bearing pre-load must be adjusted. Here, I am using a HD spanner wrench to thoroughly snug the bearings. I am using a dial indicator with a magnetic base to check backlash. Using the rag on flange/wrench on bolt technique sure makes an easy job of developing a readable pattern. I wish all my patterns looked like side with factory .079" shim. Nice coast.

High pinions are known to have potential oil starvation issues with the outer pinion bearing...this oil slinger is insurance (Toyota p/n 41214-60010 from or The new pinion seal. Spreading some gear oil around to prevent dry start-up/pre-mature wear. There has always been some confusion due to the factory pinion being 30 splines and the after-markets are 27 spline. Using the Yukon 27 spline flange on the 27 spline after-market pinion. Red Loctite is extra insurance...possibly a little overkill(blue should be ok, too)

Final assembly and torqueing

Developing enough tightening torque has never been an issue for me. About 200 ft/lbs is the target area. Loading everything onto the carrier at the same time is a bit tricky but it can be done. Getting the spanner adjusters in the right groove is important. Carrier bearing pre-load (CBPL) is important in order to minimize ring gear deflections under high loads. A machinist trick....rap on the safe areas on the bearing towers and rotate the pinion at the same time to allow the bearings to equalize in tension and find their "set". It may be found that the spanners appear to loosen up some during this process. Repeat the process until the proper CBPL has been developed. Tighten the bearing bolts to 75 ft/lb.

Verify backlash which is .007" in this case. One more pattern check. All is good. Good coast. Last step is to loctite and tighten the spanner clips. Some documentation of a pro install.

This install gets a thumbs up from Zuk!

Check back for links to future articles about the Tacoma swap!

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