Dual transfer-case conversion
Toyota trucks and 4Runners are found much more frequently on trails these days than they used to be. A big reason for this surge in popularity has been the common availability of lower-ratio transfer-case gearing for these rigs. Dual transfer-case setups and low gearsets have been readily available for all gear-driven transfer cases.
But beginning with the '85 model, a chain-driven transfer case of lighter design was also used in automatic-transmissioned vehicles, and, from 1988 on, in V-6-equipped Toyotas (trucks with four-cylinder engines have come with either style, depending on type of transmission). Although several manufacturers have looked into the possibility of stuffing a lower gearset into one of these cases, doing so simply has not been practical.
Marlin Crawler has dual transfer-case setups for the older-style gear-driven transfer-case Toyotas. The Toyota transfer case has two major sections: the front reduction box, which selects between high and low gear ranges; and the rear portion, which selects between two- and four-wheel drive. In a dual-case setup, a machined-aluminum adapter plate mates a second gear-reduction box from a donor T-case to the front of the stock transfer case. Marlin Crawler also has a kit to add an older-style gear-driven transfer case to a newer-model truck that originally came equipped with a chain-driven transfer case.
However, until recently, if you had a Toyota Tacoma or newer-model 4Runner, you had no options for lower transfer-case gearing. Two factors lead to this situation. First, as noted, all Tacomas and newer 4Runners use a chain-driven transfer case. Second, when Toyota introduced the Tacoma in late 1995, its engineers moved the front output of the transfer case from the passenger side (where it had been since 1979) to the driver side. Marlin Crawler has come up with a solution for Tacoma owners that allows the installation of a dual-case setup that adds an additional 2.28:1 or 4.7:1 gear reduction for low-low transfer-case ratios of 5.9:1 or 12.1:1. The company's MC09 kit mates an early-style reduction unit to the back of your Tacoma's transmission and then mates the back end of the reduction unit to the front of your stock Tacoma's transfer case.
This allows you to keep the driver-side front driveshaft and still mate to your stock front axle assembly. Both outputs, however, are relocated about 8 inches rearward, necessitating lengthening the front driveshaft and shortening the rear driveshaft.The kit is available for both four-cylinder and V-6 applications, and for five-speed and automatic transmissions. With the addition of this new crawler kit, Tacoma and late-model 4Runner owners can now enjoy the benefit of low-low gears that other Toyota owners have had for a number of years. Owners can achieve final drive gear ratios of more than to 200:1.
Follow along as Rocky Gleason from Marlin Crawler shows us how one of the new Tacoma transfer-case kits goes together.