Toyota Axle Swap

 

   
 
 

Toyota Axle Swap

Axles have always been at the back of my mind every since starting the buildup of my Samurai.  I really wasn't too worried when I ran my 30" tires or even my 32" tires as long as I kept a light touch on the go pedal.  Things changed when I bought the 33 x 15.50 Swampers.  That little voice in my head started reminding me how small my axles were and I think I drove with more apprehension than before.  The biggest problem was that with the bigger tires I could try bigger obstacles which usually led to getting stuck in more difficult situations.  Things came to a head on our second exploration of the Lost World trail.  On second examination of the pictures of the spot where I broke a front axle, it didn't look that hard, but the right combination of weight transfer and tire wedging proved too much for the stock axle.  So like everything in the rockcrawling world,  you build it, find the weak spot and then build it stronger. 

A lot of the information I am going to present here comes from scouring the various message boards on the internet.  Toyota axle swaps have been done many times before so I am not breaking new ground.  Also these are not the only suitable axles for swapping under a Zuk, certain year Wagoner's have full width Dana 44's with the proper offset diff for the Zuk drive train.  I won't go into hybrids or custom axles because the sky is the limit there.  Based on my reading here's some of the reasons why I chose the Toyota axles:

1.  Cost.  You can pick up 80-85 Toy axles for as low as $100 each.  The later the year, the better the front housing is gusseted from the factory.  

2.  Aftermarket support.  Limited slip, locker, ARB, or spools are readily available for the 8" Toyota rear end as well as a wide selection of ring and pinion ratios.

3.  Removable third member.  Just like the Samurai.  This makes it real easy to install gears/lockers.  Also the pinion flanges can easily be re-drilled to accept the Samurai drive shaft hole pattern and vice versa.

4.  Brakes use the same threaded fittings, 10mm X 1.0. For the front, use Napa brake line #38688, approx 22-23" long with a female connector at each end, connect one to the Zuk hard line, one to the Toyota caliper (if you already have extended brake lines for your Suzuki, you don't need to buy new ones).  For the rear the same line can be used to go between the hard line on the frame and the hard line on the axle.

5.  Flat top knuckles.  With the stock knuckles you can easily make or buy a steering setup that puts the tie rod and drag link above the springs.  Note:  If you want to use a hi-steer setup you will have to move your steering box forward.  A standard crossover setup will allow you to keep your steering box in the stock location.

6.  While still being a lot heavier than the stock Samurai axles, these axles do weigh less that the Dana 44's and the pumpkin is smaller.  

7.  Strong axles.  Based on data I have found on the internet ( one source here: http://performanceunlimited.com/illustrations/frontaxles.html), the Toyota axles are 30 spline with the smallest diameter (weakest point) being approx. 1.24".  A front Dana 44 axle's smallest diameter is 1.128", most of them are also 30 spline.  For the front the Dana 44 swap has an advantage because the Toyota front axle uses a birfield joint (though much larger than the Samurai birfield).  So if you want 38"+ tires the Dana 44 swap will be a better way to go in the long run.  My goal is 35" tires so I believe the Toyota axles will be perfect when combined with the light weight of the Samurai. 

8.  Axle width. From what I have read the Toyota axles are 5" wider than the stock Samurai axles.  How wide is good is a debate that will never end.  In many cases wider is better but in just as many cases your may be forced to take a very difficult line because you cannot fit thru an opening.  I am pretty happy with my Zuks stance as it is so based on my calculations I will be 1.5" wider than I am now using common 3.75: backspaced rims and the Toyota axles. Here's some additional axle width information I found on the web:

Stock Toyota front axle measurements for comparison:
55.5" wide, 29" spring perch centers, '79-85 Toyota trucks and 4runners
63.5" wide, (set up for coil springs) 90-97 FJ80 and FZJ80 Landcruisers
'86-95 IFS front end is about 58.5" wide
'93-98 T100 IFS front end is about 65" wide 

Toyota Rear Axle Widths:
55" wide, '79-85 trucks/4runners
58" wide, '86-95 trucks/4runners
60.75" wide, '95.5-up Tacomas/4runners
66.75" wide, '93-98 T100 trucks

The last thing I'll touch on is cost.  While this is a relatively easy swap, there are still a lot of costs that tend to add up quicker than planned.  I'll outline my costs below and update them as I go.  My target price for the swap was about $1500, I already see I will exceed that.  Here's the breakdown on what I have spent so far and remember you can find better deals the longer you look, I have given myself a month to complete the swap:

Front axles from an 85 Toyota - $250

ARB - $575

5.29 R&P - $180

R&P Install Kit - $125

Warn Hubs - $130

Rear axle from an 85 Toyota - $250  

Spool - $200

5.29 R&P - $180

R&P Install Kit - $125

Diff Guards - $17 (8" Weld on Pipe Cap)

Hy-steer Steering Arms/Pitman Arm/Tie Rod/Drag Link - $550

Misc bearings and oil seals - $60

Rotors/Brake Pads - $75

Brake Lines + Tools - $40

6 Lug Toyota Wheels w/ 3" backspacing - $281

Install of Gears & Lockers $299

Longer U-Bolts for Front $44

 

Stuff I was able to sell

Samurai axles, lockers and 4.62's - $700

Samurai Rims - $200

Trail Tough Crossover Steering - $175

Trail Tough Extended Slip Yoke - $60


Update 2-14-03 - Stuff I learned

It's been almost a year since I installed my Toyota axles and there were a few things I learned along the way that should be on the first page of this write up.

1. You need to outboard your front springs to match the Toyota spring perch spacing.  I was told you could just bolt the front axle up, you can but it'll eat spring bushings pretty quickly not to mention the springs get a slight outward bow in them.  

 2.  You can't rotate the front spring perches.  I think part of the reason my turning radius is less than desirable is my caster angles are messed up.  The stock Toyota spring eyes in front are nearly on the same plane with each other.  Keep this in mind when setting up your shackle/spring mounts.  You really can't get good caster with a shackle reverse like mine is setup and using a shackle that hangs down even lower only makes it worse.  The only solution is to cut and turn the knuckles.  The way mine is setup is useable, but the turning radius could be better.

3.  Shave your differentials.  Not only do you get a little more ground clearance but more importantly you get rid of the drain plug which eventually gets ground down to nothing.  Here's a good link to some info on how this is done or here.

4.  5.29 gears have held up well.

5.  Toyota axles under a Zuk with a stock 1.3 and 117:1 crawl ratio are darn near bulletproof.  I initially ran 35" tires and then switched to 37" tires and the axles have held up beautifully.  If you do need more strength, longfields are available to replace the stock birfield joint up front and chromoly rear axles are also available for the rear.


 I had never seen taken apart a Toyota axle before, much less tried to pick one up.  While a single person can pick up a Zuk axle, it took 3 of us to get the front Toyota axle up on my workbench!  It looked like the oil seals where shot as the knuckles were fill with gear oil.  after stripping the axle down I took a few pictures comparing the stock Samurai axles to the Toyota ones, I wasn't expecting as big a difference as what I found.

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The picture above shows a stock Samurai rear axle next to the Toyota rear axles.  Also the rear wheel bearings on the Toyota axle look to be at least 50% bigger that the Samurai ones.

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The biggest difference is in the front.  The first picture shows the 22 spline Samurai axle next to the 30 spline Toyota axle.  The second picture compares the two birfield joints, note the Samurai unit of the left has a additional ring added to it for strength, so a stock one is even smaller.  You'll also noticed the Toyota birfield has a pair of flats on it which allow it to fit into the knuckle when they are oriented vertically.

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