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Toyota Pickups & 4Runners - Weak Links, Strong Fixes

Posted in How To on July 1, 2005 Comment (0)
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Toyota Pickups & 4Runners - Weak Links, Strong Fixes

Toyota pickups and 4Runners are currently enjoying a popularity that makes them nearly as common on the trail as Jeeps. Their light weight, compact size, and simple engineering make them perfectly suited for remote, technical trails, while their wheelbase helps them scamper up steep climbs. Despite all of these benefits, there are weak links that need to be addressed in order to ensure increased reliability. Beyond lift, lockers, and tires, here are some of the problems unique to Toyotas that should be addressed before you hit the trail.

Weak link: Manual transmission shifter bushings
Models affected: All pickups and 4Runners
What happens: Aisin transmissions used by Toyota employ a ball-and-socket shifting mechanism that pivots on a rubber bushing. Over time, the leverage and exposure to gear oil can cause the bushing to break down, resulting in vague, sloppy shifts and a large amount of movement in the shifter when the vehicle is in gear.
Sturdy fix: Replacing the bushing is as easy as removing the entire shifter assembly from the top of the transmission and disassembling the shift lever. After removing the C-clip that holds the shifter to the base, all of the ground-up pieces of the old bushing can be flushed out so that a new bushing can be lubricated and installed. Reassembly will result in tighter shifting at a fraction of the price to open up the transmission for service.
Contact: Your local Toyota dealer

Weak link: Timing chain guides
Models affected: '84-'95 pickups and 4Runners equipped with the 22R or 22RE engine
What happens: In 1984, Toyota switched from using metal timing guides to plastic guides in its four-cylinder engines. This may have sounded like a good idea at the time to some bean counter, but over time the timing chain tensioner can loosen and the chain can eat through the plastic guides. Once the guides break, the chain begins slapping against the timing chain cover and can eat through a coolant passage.
Sturdy fix: DOA Racing Engines offers metal-backed guides that retrofit in place of the plastic guides and are guaranteed for the life of your motor. These guides can be purchased individually or as part of a kit with a new timing chain and all necessary seals and hardware.
Contact: DOA Racing Engines

Weak link: Push-pull steering system
Models affected: '79-'85 pickups and 4Runners
What happens: The stock push-pull steering works well in stock form, but once a pliant suspension lift and larger, heavier tires are added, the system becomes less reliable.
Sturdy fix: 4x4Labs manufactures a crossover steering system that places the drag link above the axle centerline, along with the tie rod behind the axle and above the springs. This provides less vulnerability, more strength, and more precise steering with the proper Ackerman angle. The kit replaces the stock steering box with a unit from a later model ('86-'95). Each kit is custom made for your vehicle and features billet-steel steering arms, and large 1-ton Chevy or FJ-80 tie-rod ends are used for increased strength.
Contact: 4x4Labs.

Weak link: Idler arm
Models affected: '86-'95 pickups and 4Runners
What happens: When running larger-than-stock tires on the stock IFS, the idler arm becomes stressed to the point that it sometimes fails.
Sturdy fix: To prevent the idler arm from bending during heavy trail use, Downey Off Road offers a bolt-on idler-arm brace that strengthens the steering assembly and offers greater reliability. The part bolts to the frame with handtools and comes cadmium-plated for rust resistance and long-lasting good looks.
Contact: Downey Off Road

Weak link: Independent front suspension
Models affected: '86-'95 pickups and 4Runners
What happens: In 1986 Toyota switched from a solid front axle to independent front suspension. The IFS offers a smooth ride, but it is less durable than the earlier solid axles and can be expensive to lift properly.
Sturdy fix: Due to similarities in frame widths, it is possible to retrofit a solid axle from an '85-or-older pickup into your IFS truck or 4Runner. All-Pro Off-Road offers packages ranging from spring hangers and shackles to steering and all-inclusive kits.
Contact: All-Pro Off-Road

Weak link: Lack of torque
Models affected: All pickups and 4Runners equipped with the 20R, 22R, or 22RE engine
What happens: Toyota drivetrains are stout and will live forever behind the 129 lb-ft of torque produced by the 22R motor. This lack of torque leaves something to be desired, though, when traversing tough trails.
Sturdy fix: Instead of swapping in a larger motor and sacrificing the weight balance, fuel economy, and simplicity of the drivetrain, many owners opt to add a second transfer case with an adapter from Marlin Crawler. This allows twice the torque multiplication and also relieves the angle on the front driveshaft. Another path to lower gearing is numerically lower gears that can be installed in your existing transfer case, such as those available from Advance Adapters. If your budget allows, consider a replacement 20/22R engine. LC Engineering sells all sorts of replacement parts for these engines, as well as complete assemblies specially tuned for off-pavement use.
Contact: Marlin Crawler, Advance Adapters, and LC Engineering

Weak link: Stock two-core radiator
Models affected: '84-'95 pickups and 4Runners equipped with the 22R or 22RE engine
What happens: The stock two-core radiator found in 22RE-equipped pickups and 4Runners is adequate for most uses, but when idling down the trail all day with only limited airflow, the coolant temperature can start to rise.
Sturdy fix: An easy upgrade involves using a three-core radiator from an '86-'87 22RTE turbo pickup. This radiator is a direct replacement for '84-'88 pickups and 4Runners, and offers additional cooling.
Contact: Your local Toyota dealer

Weak link: Frame around the steering box
Models affected: '86-'95 pickups and 4Runners
What happens: Though not as common as with Jeeps and Chevys, large, heavy tires can tax Toyota steering components and cause the frame to crack around the steering box.
Sturdy fix: Front Range Off Road Fabrication sells a kit that can be welded to both sides of the frame to sandwich this area with thicker, stronger material. The plates are tapered to prevent stressing adjacent areas on the frame and fit '86-'95 steering boxes.
Contact: Front Range Off Road Fabrication

Weak link: Starter brushes
Models affected: All pickups and 4Runners
What happens: After cranking the engine over for hundreds of thousands of miles, the starter motor can begin to spin slower and slower. Eventually this can leave you stranded on the trail without the ability to turn over the engine.
Sturdy fix: This problem is often just a matter of worn contacts, which can be replaced with factory parts for a fraction of the cost of a new or rebuilt starter. This problem is so common that 4Crawler Off Road stocks starter contacts for all models of Toyota pickups and 4Runners.
Contact: 4Crawler Off Road

Weak link: Front shock towers
Models affected: '79-'85 pickups and 4Runners
What happens: Toyota front shock towers are not tall enough to fit long-travel shocks. With supple leaf springs and longer brake lines, the shocks become the limiting factor and the shock mounts can rip off the frame if they have to support the weight of the axle and wheel.
Sturdy fix: Marlin Crawler has designed replacement shock hoops made of 1 1/2-inch-round, 0.120-wall tubing that are stronger than the stock pieces and allow for much longer shocks. The new hoops weld to the frame and include tubular gussets for even greater strength.
Contact: Marlin Crawler

Weak link: Birfield joints
Models affected: '79-'85 pickups and 4Runners
What happens: Instead of using U-joints on the steering axle, Toyota used a closed-knuckle design with so-called Birfield joints. For many years, the Birfields have been considered the weakest link in the Toyota drivetrain. They are messy to repair and prone to breakage, particularly during sharp turns or while backing up.
Sturdy fix: Now troublesome stock Birfields can be replaced with heat-treated Longfields from Longfield Super Axles. These upgraded Birfields have undergone a special process to make the part less brittle, and thus less prone to cracking under severe loads.
Contact: Longfield Super Axles

Weak link: Rear upper shock mounts
Models affected: All pickups and 4Runners
What happens: Similar to the front, the upper rear shock mounts are located on the Toyota frame and do not offer enough room to run extended-length shocks necessary for gobs of wheel travel.
Sturdy fix: Off Road Solutions offers a tubular shock mount that welds in between the framerails and provides increased frame rigidity and allows for 12-inch-travel shocks. The shocks are angled towards each other in order to allow for the longest length possible and still fit under the bed.
Contact: Off Road Solutions

Weak link: Blower resistor
Models affected: '79-'95 pickups and 4Runners
What happens: One of the benefits of driving a Toyota pickup is the enclosed cab. Having the A/C on in the summer or running the heater on a snow run will make you the envy of your Jeep friends. Sometimes though, the fan stops working on all but the highest speeds
Sturdy fix: This happens when the resistor that provides resistance to the blower motor burns out. The fix is easy and cheap, but the resistor can be hard to locate. It can be found beneath and behind the glovebox on Toyota pickups and 4Runners.
Contact: Your local Toyota dealer

Weak link: Transfer case output shaft
Models affected: All pickups and 4Runners equipped with the 20R, 22R, or 22RE engine
What happens: The stock output shaft in the Toyota geardriven transfer case has a machined depression behind the teeth near the center of the shaft. This depression can become a point of failure when the drivetrain is bound up, particularly after other components in the driveline have been upgraded.
Sturdy fix: All-Pro's heavy-duty output shaft removes the groove next to the dog clutch that is prone to failure, and replaces the 30-spline clutch hub with a stronger 31-spline unit. The result is a shaft that is 0.215-inch larger than the shaft it replaces. The shaft and clutch hub are made from high-quality 8620 gear steel.
Contact: All-Pro Off Road

Weak link: Rear tire rub
Models affected: '79-'85 pickups and 4Runners
What happens: When long-travel suspensions with gobs of travel are added to the rear of solid-axle Toyota pickups, the tires can rub on the frame and limit articulation.
Sturdy fix: Retrofit the rear axle out of an '86-or-newer Toyota. These axles utilize the same 8-inch third member, but are 3 inches wider. Additionally, the later-model rear axles have larger drum brakes for improved stopping power.
Contact: Your local wrecking yard

Weak link: Transfer-case crossmember
Models affected: All pickups and 4Runners
What happens: The stock transfer-case crossmember is a stamped-steel piece that is flimsy and hangs down excessively below the frame. This stock crossmember also provides no protection for expensive dual transfer-case systems.
Sturdy fix: BudBuilt manufactures a replacement crossmember and skidplate that bolts in place of the factory piece. The BudBuilt unit provides an additional 2 inches of ground clearance and is constructed of 3/8-inch laser-cut, hot-rolled, pickled, and oiled steel.
Contact: BudBuilt

Weak link: Axle drain plug
Models affected: All pickups and 4Runners
What happens: Unlike Dana axles, Toyota axles use a removable third member, much like a Ford 9-inch. The Toyota axles have a hex-shaped drain plug on the bottom to facilitate easy fluid changes. In fact, it is so easy, the plug often loosens up and removes itself on the trail.
Sturdy fix: To combat this, the hex-head plug can be replaced with a low-profile countersunk Allen-head plug (Toyota PN 90341-18021). The Allen-head plug is less susceptible to damage on the trail and easier to tighten if it should come loose.
Contact: Your local Toyota dealer

Weak link: Front brakes on solid-axle vehicles
Models affected: '79-'85 pickups and 4Runners
What happens: Solid-axle-equipped vehicles have non-vented front brake rotors with small calipers. After adding large, heavy tires, these brakes only provide marginal stopping power.
Sturdy fix: Fortunately, there are factory parts that offer improved braking performance. Larger calipers from an '86-or-newer pickup or 4Runner can be used with vented rotors from an '81-'87 FJ-60 Land Cruiser on solid front axles. A larger-bore master cylinder from an '88-or-newer V-6 Toyota is also a bolt-on replacement. Additionally, all of these upgrades will still fit beneath your 15-inch wheels.
Contact: Your local parts store or wrecking yard

Weak link: L-series transmissions
Models affected: '79-'83 pickups
What happens: The L-series transmissions used in '79-'83 HiLux pickups are not nearly as strong as later-model W-series transmissions. They are prone to bearing failure, and their short length makes for a steep front driveshaft angle.
Sturdy fix: A later-model W56 transmission will bolt right to the stock motor and transfer case, but it is 4 1/2 inches longer and requires driveshaft work and a new clutch. Front Range Off Road Fabrication produces transfer-case crossmembers to accommodate the increased length. If all of this sounds like too much work, Marlin Crawler offers heavy-duty L-series transmissions featuring larger bearings and helical-cut gears that are reported to be 30-percent stronger than the stock tranny.
Contact: Front Range Off Road Fabrication and Marlin Crawler

Weak link: U-bolts and spring plates
Models affected: All pickups and 4Runners
What happens: From the factory, Toyota leaf springs are connected to the axles with U-bolts that are pointed towards the ground. Not only does this rob ground clearance, but the U-bolts can become bent or deformed after coming in contact with trail obstacles, after which time they are nearly impossible to remove.
Sturdy fix: All-Pro Off Road sells a kit that flips the U-bolts so they are facing upward and free from harm. The kit includes 1/4-inch spring plates and new U-bolts, as well as relocated lower shock mounts that must be welded to the axlehousing.
Contact: All-Pro Off Road

Weak link: Differential breathers
Models affected: All pickups and 4Runners
What happens: From the factory, Toyota differentials only have a breather cap to allow for heat expansion. When making stream crossings, water can enter the differentials and serve you up a foamy gear-oil milkshake. If left unchecked, this can cause thousands of dollars of damage to the differentials.
Sturdy fix: In order to prevent this problem, a hose barb can be used to replace the stock breather and a length of rubber hose is attached to the barb and routed to a higher location. The fitting off of a Toyota Celica intake manifold (PN 90404-51319) has the same thread pitch as the stock axle breather and works perfectly.
Contact: Your local Toyota dealer

This is the fourth installment of a series that will examine some of the common problems of popular four-wheel-drive vehicles and how to fix 'em. Past installments included Chevy fullsize trucks and SUVs (May '04), Ford fullsize trucks and SUVs (Aug. '04), and Dodge fullsize trucks and SUVs (Apr. '05). In future issues we're going to put the spotlight on Jeep and other four-wheel-drive trucks and SUVs.

Sources

Advance Adapters
Paso Robles, CA 93446
800-350-2223
www.advanceadapters.com
All-Pro Off-Road
Hemet, CA 92543
951-658-7077
www.allprooffroad.com
Marlin Crawler
Fresno, CA 93703
559-252-7295
http://www.marlincrawler.com
LC Engineering
Lake Havasu City, AZ 86403
877-505-2501
http://www.lcengineering.com
Off Road Solutions
www.offroadsolutions.com
Longfield Super Axles
253/847-8254
BudBuilt Frames and Accessories
Arcade, NY 14009
www.budbuilt.com
Doa Racing Engines
www.doaracingengines.com
4Crawler Off Road
www.4crawler.com
4x4Labs
www.4x4labs.com

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