How a Mercedes-Benz-Built Manual Transmission Became Jeep Wrangler’s First Six-Speed

The Jeep Wrangler’s first six-speed manual transmission wasn’t homegrown—it came from Mercedes-Benz. The NSG370 gearbox, originally developed for the Chrysler Crossfire, debuted under the Wrangler’s hood in 2005, marking the first time the off-road legend offered a six-speed shifter of any kind.

Built at Daimler’s Stuttgart plant, the “NSG” stood for “Neues Schaltgetriebe” (“new manual-shifting transmission”), and it brought triple-cone syncro for first and second gears, double-cone for third and fourth, and single-cone for fifth and sixth. The gearbox featured hard-finished gears to cut noise and vibration, a steel multi-rail shift system for durability, and an aluminum case to shed weight without compromising rigidity.

Its first gear ratio of 4.46:1 paired with a 4.10:1 axle and 4.0:1 transfer case delivered a crawl ratio of 73:1—impressive for its time, though the 2026 Rubicon’s 100:1 ratio leaves it in the dust. On the highway, the overdrive sixth gear (0.84:1) aimed for efficiency, though the 2005 Wrangler’s EPA ratings with the 2.4-liter four-cylinder and manual transmission remained stuck at 16 MPG city, 19 MPG highway, and 17 MPG combined—unchanged from the 2004 model’s five-speed.

The NSG370’s off-road prowess was undeniable, but its highway economy was a different story. The transmission’s legacy didn’t end with the Wrangler; it also found a home in the Jeep Liberty before Aisin took over manual duties for the JL Wrangler in 2018.

This German-engineered gearbox proved that sometimes, the best upgrades come from unexpected places.