Knowing what a transfer case does, where it is located, and how it works is important if you own a four-wheel-drive vehicle. The main function of a transfer case is to receive power from the transmission and direct it to the front and rear axles. In four-wheel-drive vehicles designed for off-road use, the transfer case allows drivers to switch between high-range and low-range gearing. Dual-range gearing is a must for off-road drivers who see many types of terrain.
How transfer cases work
The transfer case is connected to the transmission and front and rear axles via drive shafts. Power from the engine is sent through the transmission to the transfer case, which then relays that power to either the rear wheels in a two-wheel-drive vehicle, or to the front and rear wheels in a four-wheel-drive vehicle. This distribution of power is accomplished through gears or chains. Gear-driven transfer cases are stronger, but louder than chain-driven transfer cases.
There are two types of transfer cases: married and independent. Married transfer cases are basically built in to the transmission. These are most commonly found in passenger cars. Independent transfer cases are completely separate from the transmission. Trucks and SUVs typically have independent transfer cases.
Dana Model 300 transfer case
One of the best transfer cases ever built is the Dana Model 300. This cast iron transfer case is found in 1980 to 1986 model-year Jeeps, but it adapts well to many popular transmissions. Builders like it because it’s light and durable, but still provides superior performance. The Dana 300 features two-wheel drive and four-wheel drive, along with dual ranges, both high and low. It is approximately 85-lbs. and 16 inches wide.
It should be noted that there were two versions of the Dana Model 300. The 1980 version had a shorter rear output assembly that was approximately 3.5 inches. The 1981 and later versions had a slightly longer, 5.5-inch rear output housing assembly.
The Dana Model 300 improved on its predecessors, the Dana 18 and Dana 20, with helically cut rear gears. Straight-cut gears, like those in the Dana 18 and Dana 20, are typically stronger, but louder than helically cut gears. This design change was made to allow the Dana Model 300 to run more quietly when in low range.
Although compact, the Dana Model 300 transfer case can handle a remarkable amount of power. Its impressive strength combined with its compact and simple design makes it a top-rated choice among Jeep owners and builders.