Transfer Case Spotter’s Guide

    The Lowdown on OE Low-Range Boxes

    One person’s trash is often someone else’s treasure. With this in mind, we are profiling a few enthusiast-worthy OE transfer cases from U.S.-brand applications. It will hopefully help narrow down low-range shopping in the classifieds or in the junkyard.

    New Process/New Venture transfer cases are easy to identify. Early models have a rectangular ID plate screwed to the back of the case; newer ones have a round red/silver/black tag on their backsides. BorgWarner models have an assembly tag secured by one of the housing’s bolts.

    The accompanying chart gives an overview of most Detroit Three transfer cases. Listed dates are sometimes manufacturing years as opposed to vehicle model years. Also, all transfer case models can have several variations depending on application and year. All listings are part-time and chain-drive/aluminum-case unless otherwise noted.

    Dana/Spicer Model 18, Ford GPW 7700
    Identify: Outputs offset to the passenger side; an oil pan; rear PTO; output-mounted drum emergency brake; most models have twin sticks.
    Early Military (1941-1945): MB and GPW applications had a 1.97 low-range; early Ford and Bantam versions mounted with the driver side dropped.
    Early Civilian (1945-1946): Rare. They came in the CJ-1 and first few CJ-2s; 2.43 low-range.
    Mid Civilian (1946-1955): 2.46 low-range; larger 11⁄8-inch-diamter intermediate idler shaft.
    Later Civilian (1955-1971): Intermediate shaft diameter increased to 11⁄4 inches.
    Final Civilian (1966-1971): Uses the Dana 20 case casting; rear locating bore increased from 35⁄32 inches to 4; single stick.
    Lubricant: 85W-90 gear oil.
    Notes: Overdrive units were often fitted to the PTO port. Some Ford GPWs used the Early Military Model 18, while others had the 2.46-low Ford GPW 7700 transfer case.

    Dana/Spicer Model 20
    Identify: Single shifter; same casting as the later Model 18; rear output is centered.
    Low-Ranges: 2.0, 2.34, 2.46
    Lubricant: 85W-90 gear oil
    Notes: Versions also appeared in Jeep, IH, Ford, and Chevy 4x4s. Some parts are interchangeable among versions. The ’66-’72 Bronco had the T-shift with 2.46 low-range; ’73-’77 vehicles had the 2.34-geared J-shift variant. The Bronco Model 20’s sliding gear can be combined with Model 18 gears to create a 2.46 low-range in Jeep and IH Model 20s.

    Dana/Spicer Model 300
    Identify: Passenger-side front output; centered rear output; single stick; 6-bolt round mating surface; aluminum tail housing.
    Low-Range: 2.62
    Lubricant: 80W-90 gear oil
    Notes: Possibly the best OE Jeep transfer case due to durability and 2.62 low-range. The ’80 model has a 31⁄2-inch rear output housing. This increased to 51⁄2 inches in 1981 to fit larger speedo gears. The Model 300 served as the model for the aftermarket Atlas transfer case.

    BW 1305/BW 1339
    Identify: Outputs offset to the passenger side; the aluminum case is split laterally; 1339 models (shown) have a gear-reduction box.
    Low-Range: 2.57 (BW 1339)
    Lubricant: Special fluid
    Notes: Unveiled in the ’73 Wagoneer, the Quadra-Trac BW 1305 was the first mass-production chain-drive/aluminum-housing transfer case. This full-time unit didn’t have a low-range. The BW 1339 version added a planetary gearbox to produce a low-range. This transfer case has an internal differential, which can be locked by a glovebox-mounted vacuum switch to split torque evenly front to rear. Rebuild parts are rare, although MileMarker offers a part-time conversion kit and an overdrive chain. The Model 18 is a direct replacement.

    BW 1350
    Identify: Ribbed magnesium case
    Low-Range: 2.48
    Lubricant: ATF
    Notes: Electric and manual shift; in ’83-’93 Ranger and ’84-’90 Bronco II/Explorer.

    BW 1356F
    Identify: Ribbed magnesium case, long aluminum tailshaft housing
    Low-Range: 2.69
    Lubricant: ATF
    Notes: The 1356 replaced the 1345 in the 1987 Bronco. It was in the Bronco through 1996 and in F-Series trucks and motorhome chasses from 1988 to 1991. Manual (pre-1992) and electric shift versions were made.

    Identify: Aluminum case; driver-side front output.
    Low-Range: 2.62
    Lubricant: ATF
    Notes: It looks similar to the NP207 but has a 23-spline input shaft. Found in ’80s Cherokees and pickups, it is the heart of the Command-Trac system. Dodge and Jeep versions have bolt-on yokes; others have a slip-yoke.

    Identify: Cast-iron housing
    Low-Range: 1.96
    Lubricant: 85W-90 gear oil
    Notes: Many of these full-time transfer cases have been converted to part-time with manually locking front hubs using a Doug Nash-designed kit, now sold by MileMarker. Depending on OE application, input spline counts are 10, 28, and 32.

    Identify: Aluminum output and input retainers; front output can be offset to either passenger or driver side; rear center output; rear cover is round and has three bolts; a divorced version has a yoke on the input; some have a rear slip yoke
    Low-Range: 1.96
    Lubricant: 85W-90 or heavier gear oil.
    Notes: The king of heavy-weight light-duty transfer cases, its main compromise is low-range gearing. Aftermarket upgrades include lower-gear gearsets and piggybacks as well as twin sticks. Each U.S. manufacturer, including IH, used the NP205 at some point, and six different input/output versions exist.

    NP/NV 241
    Identify: 6-bolt front face. Front output is either on the driver side (IFS) or passenger side (solid axle). Early speed sensors are mechanical, later are electronic.
    Lubricant: ATF
    Low-Range: 2.72
    Notes: The 241OR Rock-Trac version (shown) in the Wrangler Rubicon is revered for its 4.0 low-range and fixed output yoke with electronic speed sensor. The housing has more ribs than the NP241D found in Dodge trucks. The Dodge version also has a long slip yoke housing. Input shaft spline counts vary depending on duty rating: 23, 27, 29, 31 and 32. The Dodge/Ram 1⁄2- and 3⁄4-ton version is designated 241DLD; the 241DHD 1-ton model includes a PTO output.

    NP 207
    Identify: Aluminum case, driver-side front output.
    Low-Range: 2.60
    Lubricant: ATF
    Notes: One of the weaker Jeep transfer cases, it was in ’84-’87 XJs and the ’87 YJ.

    NP/NV 242
    Identify: 6-bolt front face; longitudinally ribbed case; rear outputs can be either fixed or slip-yoke.
    Lubricant: ATF
    Low-Range: 2.72
    Notes: This transfer case offers a driver-selectable full-time mode, which splits front/rear torque 48/52 percent. It also has “normal” 4-Hi and 4-Lo. The Hummer version has stronger 32-spline shafts, a 6-pinion differential, a wider chain, and a cooler. Jeeps (shown) have 21- and 23-spline input shafts, depending on OE transmission. The 242 is durable, and replacement parts are plentiful.

    NP/NV 231
    Identify: Driver-side front output; centered rear output; 6-bolt front face on Jeep and Dodge, and 5-bolt front face on GM.
    Low-Range: 2.72
    Lubricant: ATF
    Notes: One of the most popular transfer cases, a 231 version appears in many recent GM and Chrysler/Jeep 1⁄2-ton applications (231J shown). Early models use a cable-driven speedometer. Electric speed sensors appeared in 1992. GM 231C models can be adapted to Jeeps if many parts are mixed and interchanged. Jeep versions (14 configurations were made) have varying input gears depending on their OE transmissions. Also, non-TJ models have a slip yoke, which enthusiasts often convert to a fixed yoke. The heavier-duty 231HD appears in the ZJ Grand Cherokee, and the 231HDD is in Ram 1500s (12 Dodge versions were built). Many replacement and upgraded parts are available.

    NV 261/NV 263
    Identify: Magnesium case
    Low-Range: 2.72
    Lubricant: ATF
    Notes: The 261 is mechanical shift; the 263 (263GM shown) is electric shift.

    NV 271/NV 273
    Identify: Magnesium case
    Low-Range: 2.72
    Lubricant: ATF
    Notes: Basically the same case, the 271 has a manual shifter and the 273 (shown) is electronically shifted; found in Ram and Ford HD trucks.

    Make Model Application Years Notes
    Ford Dana 20 Bronco 1966-1977 Cast-iron, gear-drive
    Dana 21 F-Series 1965-1976 Cast-iron, gear-drive, single speed
    Dana 24 F-Series 1965-1976 Cast-iron, gear-drive, dual range
    NP205F F150, F250, Bronco 1973-1979 Cast-iron, gear-drive, direct and remote mount
    NP208F F150, F250, Bronco 1980-1986 Aluminum case
    NV263F 3⁄4-, 1-ton trucks, SUVs 1999- Magnesium case, electric shift
    NV271F F250-F550 1999-2010 Manual shift, aluminum case
    NV273F F250-F550 1999-2010 Electric switch, aluminum case
    BW1345F F250 1980-1992 Magnesium case, manual shift
    BW1350F Bronco II, Ranger, Explorer 1983-1989 Magnesium case, manual & electric shift
    BW1356F F150, F250, Bronco 1987-1996 Magnesium case, manual & electric shift, slip yoke
    BW4404F Explorer, Mountaineer 1996-2001 Magnesium case, electric shift, viscous coupler
    BW4405F Explorer, Mountaineer 1995-1999 Electric shift
    BW4406F F150, F250, Expedition, Navigator 1998-2002 Electric and manual shift
    BW4407F F250, F350 1996-1998 Similar to 1356 but with a rear output yoke, manual shift, PTO option
    GM Rockwell T221N K-Series Pre-1970 Cast-iron, 1.94 low-range
    Dana 20 Blazer 1969-1973 Cast-iron, gear-drive, somewhat rare
    NP203C Blazer, K-Series 1973-1979 Full-time, cast-iron, chain-drive, behind manuals, TH350, TH400
    NP205C Blazer, K-Series 1966-1984 Cast-iron, gear-drive, behind SM465, TH350, TH400
    NP207C S10, S15 1983-1987 Aluminum case, manual shift
    NP208C Fullsize pickups, Blazer, Jimmy 1981-1988 Aluminum case, synchro and nonsynchro versions
    NP231C S10, S15 1992-2003 Aluminum case, cable and electric speedo
    NP233C S10, S15 1992-2003 Aluminum case, electric shift
    NP236C Blazer, Jimmy 1998-2003 Aluminum case, electric shift, male splines on front output shaft
    NP241C Blazer, Jimmy, Yukon, Tahoe, Suburban 1987-1998 Aluminum case, manual shift, right and left drive models
    NP242C Hummer H1 1992-2001 Aluminum case, integrated cooler
    BW4484 Hummer H2 2001-2009 2-piece magnesium case, AWD mode, electric shift
    NP243C Yukon, Tahoe, Suburban 1996-1999 Aluminum case, electric shift, behind 4L60E, 4L80E
    NP246C Yukon, Tahoe, Suburban 1998-2007 Autotrac, magnesium case, electric shift
    NV261C/263C GM 3⁄4-, 1-ton trucks, SUVs 2001- Magnesium case, mechanical shift (261), electric shift (263)
    BW1370C/4470C K3500 1988-2000 3-piece magnesium case, oil pump spacer plate
    BW4401C K3500 1987-2000 2-piece magnesium case, no oil pump spacer plate
    Chrysler NP203D Ramcharger, W100-W300 1973-1979 Full-time, cast-iron, chain-drive, direct and remote mount
    NP205D W100-W350 1982-1993 Cast-iron, gear-drive
    NP208D Ramcharger, Pickups 1980-1988 Aluminum case, synchro and nonsynchro
    NP231D Dakota, Durango, W150/1500 1987-2001 Aluminum case, manual shift, 2 shift patterns
    NP241D Ramcharger, W150, W250 1987-1993 Aluminum case, manual shift, right drop, 2 shift patterns
    NP241DLD, DHD Ram 2500-3500 1994-2003 Aluminum case, manual shift, 2 shift patterns, PTO
    NP242D Dakota, Durango 1997-2001 Part-time/full-time, internal differential
    NV271D Ram 2500-5500 2003-2012 Aluminum case, manual shift
    NV273D Ram 2500-3500 2003-2012 Aluminum case, electric shift
    Jeep Dana 18 1⁄4-, 1⁄2-ton bobtails & trucks 1941-1971 Cast-iron, gear-drive, 5 different versions
    Dana 20 J-Trucks, CJs 1962-1979 Cast-iron, gear-drive; also in Scouts and some early Blazers
    Dana 300 CJ 1980-1986 Cast-iron, gear-drive; IH version built in 1980
    BW1305/1339 CJ, truck, Cherokee 1973-1979 Full-time Quadra-Trac, aluminum case
    NP200 Kaiser M715-M726, Jeep dualie trucks 1960-1970 Cast-iron, gear-drive, divorced, twin stick
    NP207J CJ, XJ, YJ 1983-1988 Aluminum case, manual shift
    NP208J FSJ 1980-1987 Command-Trac, aluminum case, manual shift
    NP219J FSJ 1980-1983 AWD, viscous coupling
    NP228J FSJ 1986 Aluminum case, vacuum & mechanical shift, no viscous coupling
    NP229J FSJ, XJ 1987-1985 Aluminum case, vacuum & mechanical shift, viscous coupling
    NP231J YJ, TJ, ZJ, WJ, XJ 1987-2006 Aluminum case, manual shift, slip yoke
    NP241OR Wrangler Rubicons 2003-2014 Rock-Trac, reinforced aluminum case, fixed yoke
    NP242J XJ, ZJ, WJ, KJ 1987-2004 Selec-Trac, torque-biasing
    NP245J XK Commander, WK2 Grand Cherokee 2005- Quadra-Drive II, aluminum case, full-time, with electric shift
    NP247J WJ 1999-2004 Quadra-Trac II, aluminum case, full-time, pump coupler
    NP249J Grand Cherokee, XJ 1993-1998 Quadra-Trac, aluminum case, full-time, viscous coupling
    NV147 WJ 2004 Quadra-Trac I, full-time, single range