2006 Ultimate Adventure - 2007 Toyota FJ Cruiser Build Part 3 - Bumper, Axle & Suspension

6. We also noticed that the stock rear axle pinion was offset roughly an inch towards the passenger side in order to keep the driveshaft away from the stock fuel tank during articulation. We will no doubt need even more offset since the rear should be a bit more flexible than stock, but the actual amount of pinion offset will need to be determined after we mock up the suspension. Note how we used a straightedge to measure wheel mounting surfaces since it is not always easy to measure directly from those points.

7. Up front things are even trickier because we need to estimate where the pumpkin will sit, while at the same time measuring around the existing IFS. If you have time to spare, cut all that IFS garbage out and then start measuring. McGean measured the framerails and determined that the engine oil pan sits slightly offset to the passenger side so a driver-side front differential would work best. Exactly how far offset it will be is determined by the space available, where the driveshaft will be coming from, and the type of suspension being used.

8. It is difficult to determine the width needed up front since the tires not only must clear the frame and fenders during articulation, but also during steering. Again McGean and Bundurant measured the stock WMS to WMS using straight-edge rulers. As a starting point we went with an inch wider than in the rear to assist with steering, but both our front and rear axles will be mocked up without fully welding the knuckles on so we can test-fit everything and determine if they need to be changed slightly.

9. Our FJ Cruiser came with a full-time transfer case and doesn't offer the low gearing we want to help supplement the 4.0L V-6. Most Toyota owners run dual transfer cases, but the narrow spacing between the transmission and gas tank will make that a little more challenging than we have time for. Our plan evolved to the new Atlas four-speed transfer case from Advance Adapters, which will offer us a 1:1 high range and 2.72:1, 3.8:1, and 10.34:1 low ranges while still being roughly the same length as the stock case (left).

10. We stuffed the four-speed behind the Toyota six-speed manual transmission and found that other than needing a new adapter, the fit was nearly perfect. Because the shift linkage would be a headache in the spacing available, we opted for the new cable shifters, and will show their placement in a future issue.

11. Here is the biggest hurdle with swapping the Atlas behind the six-speed. The Atlas uses an internal female style input, where the stock Toyota transfer case uses an external male style input, thus a spud shaft will need to be made to go between the six-speed and the Atlas. The splines that run into the six-speed are a unique 22-spline, 112-inch version that will require a one-of-a-kind spud shaft to be designed. Luckily for all you FJ Cruiser owners and hopefully you late-model Tacoma owners this will add the option of swapping a four-speed or two-speed Atlas behind your current six-speed manual, resulting in up to 24 gearing options.