Wikipedia

Jeep four-wheel-drive systems

This is an old revision of this page, as edited by 66.139.122.104 (talk) at 11:31, 5 February 2006 (→Selec-Trac). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Jeep uses a variety of four wheel drive and all wheel drive systems on their various vehicles.

Command-Trac

introduced along with the Jeep Cherokee (XJ) in 1984, Command-Trac was standard on XJ models built with 4WD. This system offers a basic "shift-on-the-fly" transfer case, for manual ease and assist while engaging. Although Command-Trac does include 4x4 capabilites, it can only be driven under temporary usage; most commonly for wet/slick surfaces or extreme weather conditions (rain, snow, etc.), and off-road activities. Even though Command-Trac was created over 20 years ago, it is still readily availible in Jeep vehicles (except Grand Cherokee and Jeep Commander) even now.

The Jeep Grand Cherokee is the only brand inside the company marque to totally discontinue this 4WD system from its lineup during production (unlike the XJ which entire lineup was dropped rather than Command-Trac itself). The reason behind this was due to its poor sales along with the SE trim among consumers, an improved Selec-Trac and simplistic Quadra-Trac had the convience and comfort of "Full-Time" 4WD that Command-Trac obviously lacked for luxury SUVs; it was quickly dropped from the ZJ platform in 1996

Applications

Selec-Trac

Selec-Trac also debuted with the compact Jeep Cherokee in 1984, but was a more common feature in its upscale version Jeep Wagoneer XJ. it has a shift-on-the-fly transfer-case like Command-Trac but unlike it, Selec-Trac has option of full-time 4WD (making 2WD somewhat of a novelty). Full-Time 4WD has the ability for the front and rear axels rotate to at different speeds, making driving on dry and wet surfaces possible year-round without shifting back to 2WD again; Yet all other 4x4 modes from Command-Trac are still availible.

other Jeep vehicles used Selec-Trac like Jeep Grand Cherokee, before before being discontinued on that platform in favor of the electronically-controlled Quadra-Drive II AWD system in 2005. Selec-Trac is currently only availible for the Jeep Liberty lineup.

Selec-Trac uses the New Venture Gear NV242 transfer case.

Applications

Quadra-Trac

The Quadra-Trac name is used on a variety of full-time capable systems. The first version was launched in 1973, with a new unrelated system used in the 1980s. Yet another system carried the name in the 1990s.

1970s

Quadra-Trac was the trade name for the Borg-Warner 1305 and 1339 gearcase. It was a chain-drive system introduced in 1973 on the Jeep SJ trucks behind the General Motors Turbo-Hydramatic 400 automatic transmission. It included a limited slip differential to shift torque between front and rear which could be locked with vacuum. The 1305 lacked a low-range, while the 1339 offered an optional 2.57 planetary gear.

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 feature (a clutch-pack in this case).

Applications:

1980s

The Borg-Warner system was replaced for 1980 with a New Process Gear NP207-based system. It uses a chain-driven transfer case.

Applications:

1990s

The Quadra-Trac name was later used on the New Venture Gear NV140. It is a single-speed system which normally sends 48% of torque to the front and 52% to the rear. A brake-based traction control system is sometimes fitted.

Quadra-Drive

Quadra-Drive (also called Quadra-Trac II) was introduced on the 1999 Jeep Grand Cherokee. In addition to the center limited-slip differential, Quadra-Trac II includes "Vari-Lok" axles front and rear which transfer torque side-to-side. The center differential is now automatic, using a gerotor oil pump. It includes a 2.72 low range as well.

Quadra-Trac II uses the New Venture Gear NV245 transfer case. It uses the same transfer case as the Quadra-Drive II. It also uses an electronic brake-based traction control system which uses speed sensors on each wheel to determine where to send torque.

Quadra-Drive II

Quadra-Drive II is Jeep's latest system. It uses the New Venture Gear NV245 like the Quadra-Trac II with an electronic limited slip differential for improved torque transfer. It also includes a 2.72 low-range gear.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Jeep_four-wheel-drive_systems&oldid=38299242"