page_title: Jeep four-wheel-drive systems
section_title: Quadra-Trac
hierarchical_section_title: Jeep four-wheel-drive systems / Quadra-Trac
caption_attribution_description: English: The selector lever for the Quadra-Trac full-time (permanent) all-time four-wheel drive (4WD) system in a 1993 Jeep Grand Cherokee (model ZJ). This luxurious sport utility (SUV) is finished in Metallic Blackberry (paint code: PM9), a deep burgundy. Equipment includes the Laredo 26F package and the Quadra-Trac full-time system. This is an early production ZJ model that was built in April 1992. The interior is in matching Crimson with cloth upholstery, that was only available at the start of the ZJ's production.
context_page_description: Jeep uses a variety of four-wheel drive systems on their vehicles. These range from basic part-time systems that require the driver to move a control lever to send power to four wheels, to permanent four-wheel systems that monitor and sense traction needs at all four wheels automatically under all conditions.
context_section_description: The Quadra-Trac name is used on a variety of full-time 4WD systems. The first version used the Borg-Warner BW1339 transfer case and was produced from 1973 to 1979. The next version used the New Process NP219 transfer case and was produced from 1980 to 1982. From 1993 to 1995 the New Process NP249 transfer case carried the name.  And from 1996 to 1998 the transfer case was manufactured by New Venture Gear  with some minor improvements and it was renamed the NV249.
  Quadra-Trac was the trade name for the Borg-Warner 1305 and 1339 gear cases. It was a chain-drive system introduced in 1973 on the full-sized Jeep line behind the AMC version of the Turbo-Hydramatic 400 automatic transmission. CJ7s also received the Quadra-Trac starting in 1976. The BW1305 included 1) a differential with a cone-type slip-limiting clutch to distribute torque between the front and rear output shafts and 2) a vacuum-switch-operated differential lock. It offered only 4WD Hi modes in full-time (open) or part-time (locked) modes.  The BW1339 added a 2.57:1 low range gearset to the BW1305, enabling 5 modes: 4WD Hi Locked, 4WD Hi Open, Neutral, 4WD Low Open, and 4WD Low Locked.
  The Jeep Quadra-Trac was differentiated from the open "New Process" Gear NP203 used by Dodge, General Motors, and Ford in that it included a center limited slip differential feature, in this case a clutch pack.
  Applications:
  1973-1979 Jeep Wagoneer (SJ)
  1973-1979 Jeep Cherokee (SJ)
  1973-1979 Jeep Gladiator
  1976-1979 Jeep CJ-7
  The Borg-Warner system was replaced with a "New Process Gear" NP219-based system in 1980 The NP219 Quadra-Trac transfer case was available in full-size Jeep Cherokee, Wagoneer, and Grand Wagoneer from 1980 through 1982.  It offered the following modes: 4H LK, 4H, N, and 4L.  In 4H (full-time 4WD High) a center differential with a viscous limited-slip coupling is used between the front and rear output shafts.  A 2.61:1 low range was engaged in 4WD Lo mode.  And in both '4H LK' (4WD Hi Locked) and '4L' modes the center differential is mechanically locked.  The 'N' mode disengages the transfer case, transmission, and engine from the axles, thus enabling flat-towing the Jeep behind another vehicle.  In 1983, the NP219-based Quadra-Trac system was replaced by the NP228/229-based Selec-Trac, adding a fuel-saving 2WD mode to the full- and part-time 4WD modes of Quadra-Trac.
  Applications:
  1980-1982 Jeep Wagoneer and full-size pickups (SJ)
  In 1993 Jeep re-introduced Quadra-Trac, this time on the Jeep Grand Cherokee using the NP249 transfer case. Like the NP219, this transfer case utilizes a center differential with a viscous coupler to provide smooth and efficient four-wheel drive operation on all surfaces.  This system has 4WD All-Time, Neutral, and 4WD Low modes.  In normal 4WD All-time mode, the center differential is open and distributes torque to both the front and rear axles.  When a difference in speed occurs between the axles, heat buildup causes the viscous fluid inside the coupler to thicken, which progressively locks the center differential thus transferring power to the axle with more traction.  In 4WD Low, the input torque is multiplied through a 2.72:1 planetary gearset. NP249 transfer cases used the viscous coupler to transfer power in both high and low ranges.
  Applications:
  1993-1995 Jeep Grand Cherokee (ZJ)
  In 1996 the NP249 was replaced with the New Venture Gear NV249 transfer case.  This added a mechanical differential lock to 4WD Low mode, making it much more durable for serious off-road use.  The NV249-based Quadra-Trac system was replaced by the NV247-based Quadra-Trac II system for the 1999 to 2004 Jeep Grand Cherokee (WJ).
  Applications:
  1996-1998 Jeep Grand Cherokee (ZJ)
caption: Quadra-Trac selector in a 1993 Jeep Grand Cherokee ZJ
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