Toying With IFS: 1992 Toyota 4Runner - 4-Wheel & Off-Road Magazine

Ali Mansour Brand Manager, 4WD & Sport Utility

Over the past few months we've used our '92 Toyota 4Runner to explore the vast desert trails and rolling countryside of Southern California. With nothing more than a 5-inch Rough Country suspension lift and a set of 33-inch Goodyear DuraTracs, the V-6 Runner has done surprisingly well. Though we've been able to cruise most of the trails that we've wanted, the lack of traction aids has hindered the Toyota's true off-road potential.

131 1103 Toying With Ifs 1992 Toyota 4runner front Three Quarter Photo 30054230

We decided early on that the 4Runner's IFS frontend would live longer if we kept the stock differential carrier open. This meant we needed a quality locking rear differential upgrade that could pick up the slack. After talking with the gear experts at G2 Axle & Gear, we decided to go with a complete third member replacement for the Toyota 8-inch rear. Packed inside the bolt-in third member is a fully automatic Detroit Locker that's paired with a numerically higher 5.29 G2 performance gearset. The addition of the rear locker will increase the 4Runner's traction, while the new gearset will help to rotate the 33-inch-tall cleats.

To install our new G2 setup, we went to the installation experts at 4Wheel Parts in Thousand Oaks, California. Though replacing a third member is relatively easy, installing the 5.29 gearset in our Toyota's 7 1/2-inch IFS differential was a very labor-intensive and precise process that we're glad we left to the pros.

Total Traction
While the jump from 4.88 to 5.29 gears was noticeable, the V-6 and auto transmission keep the 4Runner from being a real powerhouse. Without question the most apparent off-road performance gain came from adding the rear Detroit Locker. While on-road the locker offers a few handling quirks every now and again, off-road it helps tremendously with getting the Toyota down the trail. Overall, the entire setup continues to amaze us, and we look forward to seeing what else our budget-built IFS 4Runner can do.

131 1103 Toying With Ifs 1992 Toyota 4runner side Shot Photo 30054263 PhotosView Slideshow To cut down on install time, we swapped out the factory Toyota 8-inch third member for a complete replacement unit from G2 Axle & Gear. Inside of the fresh third member is a Detroit Locker that works as an automatic locker, sending power to both rear wheels when throttle input is received. Along with the new locker comes a 5.29 performance gear and bearing set from G2. Before ordering your Toyota's third member be sure to check whether the factory housing is equipped with rear ABS, as it will require a modified housing. Regearing the 7 1/2-inch IFS differential is time consuming and requires the entire differential to be removed from the 4Runner. Even with air tools, a two-post lift, and seasoned pros, the gear install took the better part of a morning.
With the third member removed, inspect your rear axle seals closely. If your axle is getting up there in years or miles, go ahead and plan on replacing the seals as well as the axleshaft bearings. While we had our frontend apart, we examined the four-wheel-drive shift mechanism closely. Similar to other IFS trucks, the 4Runner uses a vacuum-actuated shift fork to engage the midshaft that's located inside of the front axlehousing. So far the factory system hasn't given us any problems, but we're thinking about a future upgrade that would delete the vacuum engagement entirely. Since the factory carrier and spider gears appeared to be in good condition, we pressed on the new G2 bearings and 5.29 gearset and reassembled the 7 1/2-inch axlehousing. Though this would have been a prime opportunity to install a front locker, we felt it was best to keep the front differential open to help extend the life of the expensive IFS components.