PTOTY 4WD Systems
The Ram has one of the best 4WD systems on the market for those who yearn for rugged function and capability from a pickup. While the NVG 231D (Dodge) transfer case is basically the same unit found in Jeep Wranglers and Cherokees as well as Dakotas, for this application, the internals are strengthened and a wider chain is employed. With a 2.72:1 low range and a lever to engage it, this system is hard to beat, especially with a trussed and 4.10:1 geared Dana 44 solid axle sitting up front suspended by coil springs. Out back is a Chrysler Corporate 9 ¼-inch axle with a Dana antispin limited-slip differential. Instead of hubs, Dodge uses a vacuum-actuator located on the axletube for 4WD engagement.
Like the Ram, the Dakota also uses the NVG 231 transfer case with a 2.72:1 low range and a traditional floor-mounted lever to engage it. Most testers found this to be the slickest-shifting transfer case of the group. Also shared with the Ram is the Corporate 9 ¼-inch rear axle, which outbeefs every compact truck as well as most ½-ton fullsize trucks. Up front, Dodge uses an independent torsion bar front suspension (IFS). The front differential is an aluminum Dana 30 and houses 3.90:1 gears. The NV3500 five-speed tranny is the same unit that's now used in Jeeps and ½-ton Rams. It has a First-gear ratio of 4.0:1, making the crawl ratio more than 40:1.
The Frontier has one of the simplest 4WD systems on the market, and we like that. Automatic hubs provide 4WD engagement and require a few feet of backing before they disengage. Owners wanting manual hubs should note that it should be an easy conversion with either Nissan parts or a kit from Warn. The Corporate Nissan transfer case provides 2.02:1 low-range gearing. While that's certainly sufficient, we'd like to see deeper low-range gears, like those in the two Dodge trucks. Nissan (thankfully) uses a lever to work this case, and low range is accomplished by simply pushing down on the lever and sliding it back. A Nissan Corporate live axle rides in back, while its Corporate torsion-bar IFS sits in front.
Despite being a new design, the Tundra uses several carryover parts from the Tacoma/4Runner and the T100. In V-8 4WD models, the A340F four-speed automatic from the T100 is used and mated to the VF2BM two-speed transfer case. This transfer case, with a 2.56:1 low range, is a version of the Tacoma/4Runner 'case (VF2A) modified for push-button 4WD selection. A Transfer Shift Actuator is mounted at the rear of the transfer case and selects the appropriate 4WD or 2WD function based on the 4WD position signal sent to the 4WD Control ECU. Toyota uses an A.D.D. (automatic disconnecting differential) for 4WD engagement (as with Tacoma and 4Runner), which operates much like the center axle disconnect found on the Ram but uses an electric motor in place of vacuum. The axles also are a carryover from the Tacoma/4Runner/T100 with an IFS 7.5-inch front differential and a Corporate 8-inch in the rear.