NP208 Transfer Case Specsby John Wasinski
It might surprise the average person to learn how many drivetrain parts find their way into how many different vehicles. The New Process 208 transfer case has seen use in four-wheel-drive trucks from all of Detroit's Big Three at one point or another, making for some odd bedfellows where parts interchanges are concerned.
The transfer case "increases the ratio of engine revolutions opposed to tire revolutions." The high-range ratio for the NP208 is direct, 1-to-1, and its low-range reduction ratio is 2.62:1. The NP208 was the first production transfer case by this manufacturer to use a planetary gear low range.
The NP208 has an "almost symmetrical" bolt pattern; its six-bolt circular bolt pattern is non-symmetrical, and only bolts on one way. New Process used the same bolt pattern in all vehicles, but the transfer case is installed in different positions in General Motors, Dodge and Ford trucks. The General Motors -- Chevrolet and GMC -- installation is approximately 90 degrees different from the Ford and Dodge installations, which are similar to each other.
In General Motors applications, the NP208 may have a 27-spline shaft or a 32-spline shaft. In Ford, there are 31 splines; in Dodge trucks, there are 23 input splines.
Automatic transmission fluid is used to lubricate the NP208.
The NP208 was utilized in the 1980-1987 Dodge Ramcharger, W150 and W250. Units during the first three years of production were not synchronized. Later units were equipped for four-wheel drive. In Dodge pickups, the NP208 was preceded by the NP203 cast-iron transfer case that was used from 1974 to 1979. The NP208 was succeeded by the NP241 aluminum transfer case in mid-1987. Jeep full-size Cherokees from 1980 to 1983 and Jeep J-trucks from 1980 to approximately 1986 utilized the NP208 transfer case. It was installed on full-size Jeeps with the "Command-Trac" option. In Chevy and GMC trucks, the NP208 was used in the C/K 10 and C/K 20 pickups and the Suburban from 1981 to 1986. It was commonly found in trucks with the TH350, TH400 and TH700R4 automatic transmissions. Ford trucks that use the NP208 were the 1980 to 1986 Bronco, F-250 pickup and one-ton F-350 pickup.
- Ronnie Kaufman/Blend Images/Getty Images