NAG1 W5A580 Transmission Rebuild & Repair in Glendale, AZ (Chrysler Jeep Mercedes)

Sun West Transmissions — Glendale, AZ. Free estimates, honest diagnosis and a 3-year / 40,000-mile warranty on qualifying rebuilds and replacements.

The NAG1, also known by its Mercedes-Benz designation W5A580 or 722.6, is a five-speed electronically controlled automatic. Mercedes developed it for its own cars and SUVs, and during the DaimlerChrysler years it was adopted by Chrysler, Dodge and Jeep as well. That is why you find the same basic transmission under a Chrysler 300, a Dodge Charger, a Jeep Grand Cherokee and a Mercedes sedan. It is a well-engineered unit, but it has some specific electrical and hydraulic weak spots that every owner should know about.

Sun West Transmissions in Glendale repairs and rebuilds the NAG1 / W5A580. We understand its conductor plate, valve body and limp-home behavior, and we diagnose before we recommend.

Vehicles That Use the NAG1 / W5A580

• Chrysler 300, Dodge Charger, Dodge Magnum and Dodge Challenger in many V6 and V8 versions from the mid-2000s into the early 2010s
• Jeep Grand Cherokee and Jeep Commander in certain years and engines
• Dodge and Freightliner Sprinter vans
• A wide range of Mercedes-Benz cars and SUVs

Later Chrysler rear-wheel-drive cars moved to the eight-speed 845RE and related units. We verify which transmission your vehicle has before quoting.

How the NAG1 Works

The NAG1 uses three planetary gear sets, three multi-plate clutches and three brakes, plus two freewheels in some versions. A valve body with solenoids controls the shifts, and an electronic conductor plate inside the transmission connects the solenoids and carries the internal speed sensors. On Chrysler vehicles, the transmission control module is separate, while many Mercedes applications integrate more of the electronics. When the system detects a serious problem, it defaults to a “limp home” gear, usually second or third, so the vehicle can still move.

Common NAG1 / W5A580 Problems

Limp Mode from Speed Sensor Failure

The internal input speed sensors are part of the conductor plate. When one fails, the transmission stores a code and goes into limp mode. Replacing the conductor plate, and programming where required, often solves it. Our page on limp mode explains the behavior.

Fluid Wicking Through the Connector

The electrical connector on the side of the case uses a sleeve with O-rings. When those seals harden, transmission fluid can leak or wick up the wiring harness and even reach the control module. Replacing the connector sleeve is a common repair on these units, and it should be done before the damage spreads.

Harsh Shifts and Flares

Worn clutches, sticking valves in the valve body or old fluid cause harsh 2-3 shifts, flaring and delayed downshifts. Adaptive values may also need resetting after repairs.

Torque Converter Shudder

A shudder at light throttle on the highway usually involves the converter clutch and fluid condition. Left alone, converter wear contaminates the fluid. Read about torque converter replacement.

Overheating in Desert Driving

Sporty sedans and SUVs in Phoenix heat build transmission temperature quickly, especially V8 models and vehicles that tow. Old fluid in these units breaks down and accelerates wear.

How We Diagnose a NAG1

We scan the transmission module, read codes and adaptive data, inspect the connector sleeve and harness for fluid, check fluid level and condition with the proper temperature procedure and road test the vehicle. Since the NAG1 has no traditional dipstick in many applications, fluid checks need the right tools. Many limp-mode cases turn out to be electrical rather than internal damage.

NAG1 / W5A580 Repair Options

• Connector sleeve replacement to stop leaks and wicking
• Conductor plate replacement for speed sensor and solenoid circuit faults
• Valve body service or replacement
• Fluid and filter service with the correct fluid
• Complete rebuild with new clutches, seals and wear parts, valve body service and converter attention

Qualifying rebuilds are covered by our 3-year / 40,000-mile warranty with no deductible on covered repairs.

NAG1 Rebuild Cost

Cost depends on whether the fix is a connector sleeve, a conductor plate, a valve body or a complete rebuild, along with the converter and parts needed. We provide free estimates after diagnosis. See our Dodge Challenger and Jeep Grand Cherokee pages for vehicle-specific details. Financing is available.

NAG1 / W5A580 Transmission FAQ

Is the NAG1 the same as the Mercedes 722.6?

Yes, they are the same basic design. Chrysler calls it the NAG1, and Mercedes uses the W5A580 and 722.6 designations. Calibrations and some parts vary by vehicle.

Why does my car start in second gear and will not shift?

That is the limp-home mode. A failed speed sensor on the conductor plate is a common cause, but wiring and other faults can do it too.

Can fluid in the wiring harness damage the computer?

Yes. Fluid wicking up the harness can reach connectors and modules, so leaks at the connector sleeve should be fixed promptly.