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Dodge used the very strong, cast iron, New Process NP205 two speed, gear drive, part time transfer cases in various models from 1969 to 1993. From late 1974 to 1988, the NP205 was only offered in 1 ton trucks. From 1989-1993, the 205 was used in all Cummins Diesel W250 models and all W350 trucks.
All 1974-1979 Ramchargers, 1974˝-1979 W100/150, and W200/250 trucks were equipped with the combination gear drive/chain drive, full time, New Process two speed NP203 transfer case as were some W350 models. The 203 is rather unique in that the cast iron, low range unit was a actually a separate gear drive box bolted to the front of the cast iron chain drive case. The inter-axle differential was located behind the chain case inside an aluminum housing. 203's have a 1.96-1 low range. The early NP203 models had a wide, 3/8" pitch chain that has a tendency to stretch and jump the drive sprockets. Late model cases use a narrow 1/2" pitch chain that is much stronger. These later cases are quite reliable but not very fuel efficient. The NP203 was discontinued after the 1979 model year. A number of companies offered part-time conversion kits for the 203 to help boost fuel economy, however, converted 203's almost always suffer major lubrication related failures. As an interesting sidelight, the NP203 range box is now one of the most sought after used part on the market. A number of companies offer conversions to adapt the range box to more modern transfer cases for double low range capabilities.
From 1980 to 1987 Dodge used the two speed, NP208, chain drive, aluminum transfer case in all Ramchargers, W150 and W250 trucks. While not a particularly robust design, the 208 generally gives good service unless abused or poorly maintained. The 208 was the first New Process production transfer case to use a planetary gear low range. The low range ratio is 2.72:1. Early units from 1980 to 1982 were not synchronized. Late 1982 to 1987 208's in Dodge trucks are synchronized for 4 wheel drive.
From 1988 to 1997 The NP231 and NV231 light duty, chain drive transfer cases were installed in Dakotas and some light 1/2 ton trucks.
Dodge W150 and W250 trucks (except Cummins Diesel models) from late 1987 to 1993 have the two speed, NP241, chain drive aluminum transfer case. All 1994-2002 Dodge full size, 4x4's are equipped with NV241 transfer cases. Dodge 241's have a planetary low range ratio of 2.72:1. There were numerous design changes in the 241 during its production life making parts selection a bit tricky without the transfer case build tag. Starting in 1994, the stock 1500 and 2500 transfer case was the NV241DLD (Dodge Light Duty). Optional on the 2500 and standard on the 3500 was the NV241DHD (Dodge Heavy Duty).
The NP271 manual shift and NP273 electric shift, chain drive transfer cases are found in 2500 and 3500 models effective for the 2003 model year