How Jeep Snuck A Mercedes Manual Into the Wrangler

The Daimler-Chrysler merger was supposed to be a visionary power move. It was, in reality, a nine-year disaster that mostly resulted in Chrysler buying expensive German parts it didn’t need. But every cloud has a silver lining: at least one genuinely weird and fascinating piece of hardware came out of that marriage—a six-speed manual transmission built in Stuttgart that would become the Jeep Wrangler’s most capable stick shift ever.

That gearbox is the NSG370—short for “Neues Schaltgetriebe,” which is German for “new manual-shifting transmission,” because of course a Mercedes part has a German name printed on it. It first appeared in the Chrysler Crossfire, another artifact of the merger, before Jeep engineers realized they had access to something genuinely useful sitting in the corporate parts bin. Starting in 2005, the NSG370 became the Wrangler’s first six-speed manual—and notably, the Wrangler’s first six-speed transmission of any kind. The automatic stayed at five speeds until 2018.

A Transmission Built for Off-Road Punishment

What made the NSG370 special wasn’t just the extra gear. It was engineered with the kind of brutality you’d expect from a company that builds cars meant to survive the Autobahn at 180 mph, then adapted for vehicles that need to crawl over rocks at single-digit speeds.

The synchronization system was tiered by gear: first and second got triple-cone synchronization, third and fourth got double-cone, and fifth and sixth settled for single-cone. This wasn’t over-engineering for its own sake—it meant faster, smoother shifts under load, which matters when you’re working through gears on a steep trail. The gears themselves were hard-finished to kill noise, vibration, and harshness (a detail that would’ve been invisible to buyers but felt by everyone who drove it).

The transmission case was aluminum to keep weight down without sacrificing rigidity, while the multi-rail shift system was forged steel. But the real trick was the first-gear ratio: 4.46:1. Pair that with a 4.10:1 axle ratio and 4.0:1 transfer case, and the 2005 Wrangler could achieve a 73:1 crawl ratio—meaning one engine revolution moved the wheels roughly 1/73rd of a rotation. More crawl ratio equals more torque without wheelspin on technical terrain.

For highway duty, the sixth gear acted as an overdrive at 0.84:1, though “efficient” is doing a lot of work in that sentence. The 2005 Wrangler with this transmission and the base 2.4-liter four-cylinder managed EPA ratings of 16 city/19 highway/17 combined—exactly the same as the 2004 model with five gears. Sometimes an extra gear doesn’t change anything.

The Strange Legacy of Corporate Hand-Me-Downs

The NSG370 story is a perfect microcosm of everything weird about the Daimler-Chrysler era. Two companies tried to merge their best DNA, but what they actually created was a parts supply chain where German engineering got bolted onto American vehicles in ways that made sense on spreadsheets and nowhere else. The Crossfire got the NSG370. The Wrangler got it. Even the Liberty saw duty with this gearbox.

But here’s where it gets interesting: the NSG370 didn’t last forever. When Jeep introduced the JL Wrangler in 2018, they switched to an eight-speed automatic for the slushbox crowd. For the manual faithful, though, they didn’t go back to Mercedes. They went back to Aisin, a Japanese supplier that had actually built the Wrangler’s five-speed manual before the NSG370 replaced it. It’s circular logic worthy of a merger retrospective—Daimler-Chrysler pushed German parts, then Jeep ditched them and went back to who they’d worked with originally.

The Wrangler still offers a six-speed manual, so the NSG370 proved its point: Jeep owners who want to row their own gears can still do it. But modern Wranglers—like the current Rubicon—use Aisin’s transmission paired with modern hardware to achieve even better crawl ratios (up to 100:1 in current models). The German transmission was competent. It just wasn’t irreplaceable.

What It Actually Meant for Drivers

If you bought a 2005-2011 Wrangler with the NSG370, you got a transmission that was simultaneously over-engineered and perfectly suited to what Wranglers do. The smooth synchronization meant less gear grinding. The aggressive first-gear ratio meant more low-end grunt for technical terrain. The overdrive sixth meant you weren’t screaming down the highway at 3,500 rpm in fifth like earlier Wranglers were forced to do.

But practically speaking, Wrangler owners in that era were mostly doing two things: commuting in traffic and occasionally hitting moderate trails or beach runs. The NSG370 was brilliant for that workload. It was also built with the kind of bulletproof engineering you’d want from a Daimler subsidiary, which meant it held up. Wranglers with these transmissions are still running strong 20 years later, which is more than you can say for many contemporary transmissions in the automotive industry.

The NSG370 is gone now, replaced by more modern hardware from more expected suppliers. But it remains one of the best arguments that the Daimler-Chrysler merger, for all its dysfunction, at least produced one piece of hardware worth remembering. A Mercedes transmission in a Jeep isn’t a great metaphor for corporate synergy. But as an actual transmission, it was damn good.

Sources: Jalopnik