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W5A580 / NAG1 automatic (5-speed)

The Wrangler JK's German five-speed

When the Wrangler JK received the 3.6 Pentastar in 2012, it came with an automatic more modern than the 42RLE: the W5A580, a Mercedes five-speed known internally as NAG1. With a tall fifth, it dropped the revs on the highway and smoothed things out.

A licensed Mercedes

The W5A580 is, at heart, the Mercedes-Benz 722.6 (the '5G-Tronic'), which Chrysler built under license during the DaimlerChrysler era and badged NAG1 (New Automatic Gearbox, generation 1). The W5A580 code says almost everything: W for converter, 5 speeds, A for automatic and 580 N·m of allowable input torque (about 428 lb·ft). It's longitudinal, with overdrive and a lockup converter.

In the JK it arrived only with the 3.6 Pentastar (2012–2018). A point to avoid confusion: the JK with the 3.8 V6 (2007–2011) did not use this box, but the four-speed 42RLE. Outside the Wrangler, the NAG1 was very common in the Grand Cherokee WK, the Commander XK and the Liberty, behind engines ranging from the V6 to the 5.7 Hemi and the 6.1 SRT8.

Ratios and details

Converter lockup typically engages in 3rd, 4th and 5th, which helps highway economy. A quirk of this German box: it has two reverse ratios (a short 3.16 and a tall 1.93), unusual for automatics of the era, chosen by load and speed.

It's a refined, good-driving unit, though —like any modern electronic automatic— it wants its specific fluid and dislikes overheating. Kept up to date, it's the most relaxed of the automatics the Wrangler ever ran.

Specifications