Toyota 80 Series Electric Locking Differentials Retrofit for an FJ60

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So you’re wondering about putting electric lockers from an FZJ80 Land Cruiser into your older Land Cruiser eh? Well, here’s the low-down on putting them into an FJ60, though putting them into an FJ62 will be the same and putting them into a 40, 45, or 55 series is going to be pretty much the same with the major exceptions being the fact that 60/62 series axles are wider than 40/55 axles, and, depending on year, the bolt pattern on your Cruiser's companion flange on the diff and drive-shaft might be different than the bolt pattern on the companion flange of an 80 series electric lock diff.

Before you read further, if you haven’t read the TLC FAQ on Birfield.com yet, then go do it. At the very least you should read the sections on Land Cruiser axles—but it’s all super good stuff. (You may also benefit from reading 4WD 101.)

Now, because there’s so much info floating around out there about axles and differentials, we’ll do some quick defining of a few things—and also keep in mind this is for US spec Land Cruisers.

First, 80 series non-lock and electric-locking differentials are 4.10:1 gear ratio, 62s are 4.11:1, 60s are 3.70:1, 1979+ 40s/55s are also 3.70:1, and 1978 and earlier are all 4.11:1. This, of course, all applies to fronts AND rears (in case you didn't know, you need the same diff ratio front and rear or else your transfer case is gonna go boom).

Also, 1990-1992 FJ80 series Land Cruisers did not come with lockers. The 1993-1997 model FZJ80s are the years that had an option for the electric lockers.

Next, 80 series fronts have an 8 inch ring-gear, and rears have 9.5 inch ring-gear. All other US Cruisers older than an 80 series have 9.5 inch ring-gears front and rear. So, the front differential of an 80 is pretty much no good for an older LC, but the rear is golden!

All front axle assemblies of Cruisers (80 series and earlier) are "full-float" (FF). Almost all rear axle assemblies of US Cruisers pre-dating an 80 series are "semi-float" (SF). To use a stock LC electric locker in an LC, it must have a full-float axle assembly. If you want to know more about the differences between full-float and semi-float, then you need to visit the TLC FAQ or some of the more popular Internet bulletin boards.

The stock LC electric lockers need a special long-splined axle shaft in order to function. There are OEM long-splined axles available that fit 40 series axle widths (which are the same width as 45 and 55 series axles) and 60 series axle widths (which are the same widths as the 62 series axles). Some non-USA spec 60 and 70 series Land Cruisers came with factory cable locking diffs. These diffs are relatively the same as the electric locking diffs with the main difference being cable actuation instead of electrical actuation. The locking units work the same on the inside of the diff (with the exception of the 80 series fronts of course). Thus, the OEM long-splined axle shafts used for the cable-lock axle assemblies in the non-USA Land Cruisers can be used with the electric locking diffs. The long-splined axles needed are the long side front and short side rear. I have been told that for a 40 series front long-splined axle shaft you can use the long side front from a cable-locker equipped 70 series. (Note: In 1991, 70 series front axles underwent a change from the larger 9.5 ring gear to the smaller 8.0 ring gear. They also changed from cable lock to electric lock and went to the larger birfields. So, the front shaft from an electric-lock 70 series will not work in a 40 series axle--you must get one from a cable-lock equipped 70 series.) For a 60 series front long-splined axle shaft you can use the long side front from a cable-locker equipped 60 series. The short sides of 40, 45, 55, 60 and 70 series axles are the same lengths and can be interchanged. Thus, the rear long-splined short-side shaft can be found from the cable-lock equipped 60 or 70 series Land Cruisers. See the part numbers page for more info. (Side note: As you carry on with the project, you might start to think that you could maybe use the stock shaft with the shorter splines on it in an emergency if you just keep the differential locked—NOPE. You can’t do it. Believe me—I tried. The stock shaft does not have long enough splines needed to engage the side gear and the diff lock sleeve.)

So, in short, you can put an electric locking diff from the REAR of an 80 into the front of ANY older LC, you just need the special long-splined shaft, which would need to be the LONG side (inner). But, in order to put the same electric locker from the REAR of an 80 into the rear of any older LC, you must acquire a full-float rear axle assembly AND the special long-splined shaft, which, for the rear, needs to be the short side. There's a few other things needed like new gaskets and some longer diff studs as well--I'll get more specific later.

Also, if you want to put a non-lock rear diff from an 80 into an older LC, it will fit in either front or rear with no issues.

Got that? OK. Click next. And don't worry, there's plenty of pics on the following pages...

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