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The Chrysler 300 has run two main automatics over its life, and they fail in completely different ways. The 2005 to 2014 cars (and the Hemi 300C) used the Mercedes-derived W5A580 (NAG1) 5-speed, which is a strong transmission with a couple of well-known electronic weak points. The 2012-and-up 300 moved to the ZF-based 8-speed (845RE / 8HP70), which is smooth when healthy but is sensitive to fluid and software and has its own valve-body and shift quirks. Knowing which one is in your car points you straight at the likely fault.
Chrysler 300 Transmission Problems by Year
| Year Range | Transmission | Common Failure |
|---|---|---|
| 2005–2014 | W5A580 / NAG1 (5-speed) | Conductor plate / speed sensor faults, limp mode, shudder, valve body wear |
| 2012–2014 (V6) | 845RE (ZF 8HP45) | Harsh/erratic shifts, valve body solenoid faults, shudder, software issues |
| 2015–present (V6/V8) | 845RE / 8HP70 | Shift hunting, shudder, valve body, leaks, fluid sensitivity |
W5A580 (NAG1): The Conductor Plate
The 5-speed in the early 300 is a robust unit, but its Achilles heel is the conductor plate — the internal electronic module that integrates the speed sensors and valve-body wiring. When it goes bad you get limp mode (stuck in 2nd or 3rd), erratic shifts, a no-start in some cases, and speed-sensor codes. The conductor plate is a serviceable part that does not require a full teardown, which makes it one of the more affordable major fixes on the 300. These transmissions also benefit hugely from a proper fluid and filter service — they take a specific Mercedes-spec ATF (NAG1 fluid), and neglected fluid causes a lot of the shudder and shift complaints.
845RE / 8HP (2012+): Valve Body and Software
The 8-speed is a fundamentally excellent transmission — when it is right, it is one of the smoothest automatics on the road. The complaints are harsh or erratic shifts, occasional shudder, and shift hunting, and a large share of those trace back to two things: fluid and software. The 8HP is extremely fluid-sensitive (it takes a dedicated ZF 8-speed ATF, not ATF+4), and FCA released numerous transmission software updates to smooth out shift behavior. When fluid and calibration are correct and it still shifts badly, the usual hardware culprit is the valve body / mechatronic unit or its solenoids.
Repair Cost: What You Are Looking At
| Repair | Typical Cost Range |
|---|---|
| Fluid + filter service (correct fluid) | $250–$450 |
| NAG1 conductor plate replacement | $500–$1,100 |
| Valve body / mechatronic (8HP) | $1,200–$2,500 |
| Full rebuild | $2,800–$4,500 |
| Remanufactured transmission, installed | $3,800–$5,800 |
Rebuild vs Replace
On a NAG1 300, do not jump to a rebuild — a conductor plate and a correct fluid service fix the overwhelming majority of complaints. On an 8HP, verify fluid and software first; the valve body / mechatronic is the next step, and a full rebuild is reserved for actual internal clutch damage. The 300 is a heavy, comfortable car that holds up well, so if the body and engine are sound, repairing the specific fault on the transmission you have is almost always smarter than a reman of unknown history.
Chrysler 300 Parts Ship Same-Day
Doing the repair yourself or supplying your own shop? gearboxinsider.com stocks NAG1 conductor plates, speed sensors, filters, 8HP valve body parts, solenoids, and complete rebuild kits for the 300. Same-day ship before 2pm Eastern.
Shop Gearbox Insider →FAQ
What years of Chrysler 300 have transmission problems?
The 2005 to 2014 NAG1 5-speed (conductor plate, shudder) and the 2012+ 8HP 8-speed (harsh shifts, valve body, fluid/software sensitivity) are the most complained-about.
What is a conductor plate and is it expensive?
It is the internal electronic module on the NAG1 5-speed that handles the speed sensors and valve-body wiring. It is serviceable without a full teardown, typically $500 to $1,100 installed.
What fluid does the Chrysler 300 take?
The NAG1 5-speed takes a Mercedes-spec ATF, and the 8HP 8-speed takes a dedicated ZF 8-speed fluid — not ATF+4. Using the wrong fluid causes most of the shudder complaints.
Is the 300 transmission worth rebuilding?
If the rest of the car is sound, repairing the specific fault (conductor plate, valve body) is usually better value than a full rebuild or reman.