The infamous Daimler-Chrysler “merger of equals” lasted only nine years, from 1998 to 2007, and never lived up to its expectations. Instead, at least on Chrysler’s ledger, drivers were mostly treated to a Mercedes-Benz hand-me-down like the R170 platform. It first underpinned the MB SLK before finding a second life under the Chrysler Crossfire – and under the occasional project car like the Mercedes SLKerman Ghia. Meanwhile, Jeep fanatics will know that the brand’s first six-speed manual transmission also came from the German parts bin
The NSG370 gearbox was actually first used in the Crossfire, and will also be used in Jeep models like the Liberty. But the transmission was manufactured at the Daimler plant in Stuttgart, Germany. “NSG” stands for “Neues Schaltgetriebe”, which translates to something like “new manual-shifting transmission”. And to be clear, the NSG370 was not only the first six-speed manual for a Wrangler, it was the first six-speed gearbox of any kind to appear on a nameplate.
That’s because the Wrangler seems to have ditched the six-speed automatic altogether. The brand jumped straight from the five-speed slushbox for 2012-2017 models to the eight-speed unit introduced in the 2018 JL Wrangler. Note that the Wrangler is still keeping the manual with the six-speed transmission. However, the introduction of the JL series also saw the introduction of a new manual transmission source, Aisin – which was actually an older source. Aisin made the Wrangler’s five-speed manual before it was replaced by the six-cog NSG370.
Description of NSG370 six-speed manual transmission
The NSG370 was launched as part of an upgrade to the 2005 Wrangler, including the Wrangler Unlimited. Mechanical highlights started with triple-cone synchronization for first and second gears and double-cone synchronization for third and fourth gears, taking advantage of synchromesh technology to make gear changes smoother and smoother. Fifth and sixth gears had a single cone to synchronize the shifting process. As far as the physical gears are concerned, they were rigorously engineered to help reduce noise, vibration and harshness (NVH).
The gearbox also boasts a multi-rail shift system made of steel for added strength, and it relies on an aluminum case to reduce its weight without sacrificing stiffness. For off-road action, the transmission was upgraded with a faster first-gear ratio of 4.46:1. As a result, when the Wrangler was specified with its 4.10:1 axle ratio and 4.0:1 transfer case, owners could enjoy a crawl ratio of 73:1. For comparison, the 2026 Wrangler Rubicon can manage a 100:1 crawl ratio. Higher is better because the numbers basically represent how many engine revolutions are required to turn the wheels at once. In other words, you can access more torque without worrying about increasing your speed too much and spinning out of control.
At the other end of the spectrum, the NSG370 has an overdrive sixth gear with a ratio of 0.84:1 for efficient highway cruising. Of course, “efficiency” in this case was relative. The ’05 Wrangler’s best EPA rating, with the manual transmission and base 2.4-liter four-cylinder engine, was the same 16 mpg city/19 mpg highway/17 mpg combined for a similarly equipped 2004 model with a lower gear.
