P0733 on 2012-2019 Dodge Charger: Gear 3 Incorrect Ratio Causes and Fixes

What's Unique About the 2012-2019 Dodge CHARGER

The 2012-2019 Dodge Charger spans a critical transmission evolution. Early models (roughly 2012-2014) may have the 5-speed Mercedes-designed W5A580 (also called NAG1) automatic, while later models (2015+) feature the more advanced ZF-designed 8-speed transmissions (e.g., 8HP45, 8HP70, 850RE). This is crucial because failure points differ. The 5-speed NAG1 is known for failures of the conductor plate, which houses the speed sensors and can crack over time, and leaks from the 13-pin connector plug that can wick fluid up to the TCM. The 8-speed ZF units are more susceptible to software glitches requiring a reflash, valve body/mechatronics unit failures, and specific internal clutch pack issues.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is illuminated.
• Transmission may enter 'limp mode', getting stuck in one gear (often 2nd or 3rd).
• Harsh, abrupt, or delayed shifts, particularly when going into third gear.
• Transmission slipping, where engine RPMs increase but the car doesn't accelerate proportionally.
• Inability to shift into third gear; the transmission may seem to skip from 2nd to 4th.
• A clunking noise during the 1-2 or 2-3 shift.
• Reduced fuel economy.
🎬 Watch: A quick breakdown of P0733 causes and fixes.

Most Likely Causes

1. Low or Dirty Transmission Fluid 🔴 High Probability Many of the 8-speed transmissions in these Chargers are 'sealed' and have no dipstick, making fluid level checks less straightforward and leading to neglected service. The 5-speed NAG1 can suffer from water intrusion through the fill tube seal, contaminating the fluid.
   How to confirm: For the 8-speed ZF, the fluid level must be checked via a fill plug on the transmission case while the vehicle is level and the transmission fluid is within a specific temperature range (typically below 30°C/86°F for a cold check, or a higher temp for a hot check), monitored with a scan tool. 🎬 See how to properly check the 8-speed fluid level. The fluid should be pink/red and not smell burnt. For the 5-speed, a special dipstick tool is required.
   Typical fix: Perform a transmission fluid and filter change. For 8-speeds, use Mopar ZF 8&9 Speed ATF (Part #68218925AB or equivalent). For 5-speeds, use Mopar ATF+4 (Part #05013457AA).
   Est. part cost: $150-$300
2. Faulty Shift Solenoid or Valve Body 🟡 Medium Probability Solenoids are electro-mechanical parts that wear out. On the 8-speed, they are part of the mechatronics unit (valve body). Debris from aging fluid can cause them to stick or fail. On both transmission types, valve body issues are a documented cause of this code.
   How to confirm: A professional can use a scan tool to command the specific solenoid for third gear on and off to test its function. Pressure tests can also isolate a valve body issue. A Ram owner with an 8-speed and P0733 reported a diagnosis of a faulty valve body, which eventually led to a full transmission replacement after metal was found in the pan.
   Typical fix: Replace the faulty shift solenoid or the entire valve body assembly. This is located inside the transmission oil pan.
   Est. part cost: $250-$1200
3. Faulty Conductor Plate (5-Speed NAG1/W5A580 Only) 🟡 Medium Probability The conductor plate in the Mercedes-designed 5-speed transmission is a well-known failure point. It's a plastic plate housing the speed sensors and electronic circuits, which can crack or have its sensors fail from heat and age, leading to limp mode and ratio codes.
   How to confirm: This is often diagnosed after fluid issues are ruled out. The integrated speed sensors on the plate can give erratic readings. The part is visually inspected for cracks upon removal of the valve body.
   Typical fix: Replace the conductor plate, the 13-pin connector sleeve (to prevent leaks), the filter, and the fluid. Part numbers are often 52108308AB or 52108308AC.
   Est. part cost: $150-$350
4. Internal Transmission Mechanical Failure 🟡 Medium Probability TSBs for later models with the 8-speed transmissions point to specific failures of internal clutch packs. A worn or damaged 3rd gear clutch pack will slip, directly causing this code.
   How to confirm: This is a diagnosis of exclusion. If fluid, solenoids, and sensors are all good, the problem is likely internal. Finding metal shavings in the transmission pan during a fluid service is a definitive sign of mechanical failure.
   Typical fix: The transmission must be removed and either rebuilt with new clutch packs and seals or replaced entirely with a new or remanufactured unit.
   Est. part cost: $2000-$5500+
5. Transmission Control Module (TCM) Software Issue ⚪ Low Probability FCA has issued TSBs for similar platforms to update TCM software for prematurely setting incorrect ratio codes. A Jeep owner with P0733 noted that independent shops suspected a software issue because the problem disappeared when shifting manually.
   How to confirm: A dealership or qualified shop can check the current software version of the TCM against the latest available version from FCA using their diagnostic tool.
   Typical fix: Reprogram or 'flash' the TCM with the latest software.
   Est. part cost: $0-$250

Rare But Worth Checking

• Clogged Transmission Fluid Passages / Faulty Valve Body: If the transmission fluid is very old and dirty, sludge can build up and clog the small passages within the valve body, preventing correct hydraulic pressure from engaging the third gear clutch.
• Leaking 13-pin Connector (5-Speed NAG1): A very common issue on the W5A580 is a leak at the 13-pin electrical connector plug. The O-rings fail, allowing fluid to leak out. This fluid can also wick up the wiring harness and damage the Transmission Control Module (TCM), causing various codes including P0733.

Diagnosis Steps

1. Check the transmission fluid level and condition. This is the first and most important step. On 8-speed models, this must be done from under the vehicle with the engine running at a specific temperature, monitored by a scan tool.
2. Use a quality OBD-II scanner to check for any other pending or stored transmission-related codes, especially P0700 or other ratio codes.
3. Inspect the transmission wiring harness and connectors for any visible damage, corrosion, or loose connections. On 5-speed NAG1 models, pay close attention to the 13-pin connector for signs of fluid leakage.
4. With an advanced scan tool, monitor the live data for the input (ISS) and output (OSS) speed sensors to ensure they are providing a smooth and plausible signal.
5. If possible with the scan tool, command the third gear shift solenoid to activate and listen for a click from the transmission pan.
6. Drop the transmission pan to inspect the fluid for metal shavings or clutch material, which indicates a serious internal failure. This also allows for inspection of the valve body and solenoids (or conductor plate on the 5-speed).
7. If all external checks pass, the issue is likely internal to the transmission, requiring removal and inspection of the valve body and clutch packs.

Parts You'll Likely Need

• Transmission Fluid and Filter Kit

Related Codes That Often Appear With This One

• P0700 — This is a general Transmission Control System Malfunction code. It's an informational code that simply means the TCM has stored a more specific fault code, like P0733.
• P0734 — Incorrect Ratio in Gear 4. When multiple gear ratio codes appear together, it points more strongly towards a systemic issue like low/dirty fluid, a failing valve body, or a major internal failure rather than a single gear's solenoid.
• P0716 — Input/Turbine Speed Sensor Circuit Range/Performance. This code can directly cause P0733 because the TCM relies on this sensor's reading to calculate gear ratios. On the 5-speed NAG1, this sensor is part of the conductor plate.

Technical Service Bulletins (TSBs) & Recalls

• NHTSA TSB #21-011-05: Addresses a transmission shudder on the 5-speed NAG1 (W5A580) caused by water contamination in the fluid. The fix involves a triple flush procedure and sealing the transmission fill tube. While not directly for P0733, fluid contamination is a root cause.
• Generic TSB for Incorrect Ratio Codes (e.g., from Hyundai): While not FCA-specific, other manufacturers have issued TSBs (like TSB 17-AT-004 for Hyundai) that describe a procedure for diagnosing multiple incorrect ratio codes (P0731-P0736), often leading to transmission replacement if clutches are found to be slipping.

Platform-Specific Known Issues

• Intermittent Issue Resolved by Restart: A Ram 1500 owner with the 8-speed transmission experienced harsh clunking into gear and a P0733 code after the truck sat for a few days. After pulling over and restarting the vehicle, the issue disappeared completely and the truck drove normally. This points to a possible one-time electronic glitch or a low-voltage situation from the battery.
• Valve Body Diagnosis Leads to Full Replacement: On the 'Ram Heavy Duty Forum', an owner of a truck with an 8-speed transmission and P0733 code documented their repair journey. The dealer initially diagnosed a faulty valve body. However, upon dropping the pan as required by the warranty provider, they discovered metal shavings. This changed the diagnosis to a full internal failure, requiring a complete transmission replacement under warranty.
• 5-Speed NAG1 Conductor Plate Failure: The Mercedes-Benz derived 5-speed (NAG1/W5A580) used in earlier models is notorious for conductor plate failure. This component contains the speed sensors. When it fails, the TCM loses critical data, often resulting in the vehicle going into limp mode (stuck in 2nd gear) and logging various speed sensor and gear ratio codes, including P0733.

Mechanic-Grade Diagnostic Values

• NAG1 (722.6) Transmission Solenoid Resistance — expected: Between 3.3 and 6.2 ohms, measured from the TCM connector between the power feed wire and each solenoid control wire.. Failure: A reading outside of this range indicates a faulty solenoid or wiring.
• NAG1 (722.6) Transmission Temperature Sensor Resistance — expected: Between 500.0 and 2500.0 ohms.. Failure: A reading outside this range suggests a faulty temperature sensor, which can affect shift scheduling.

Scan Tool Commands That Help

• wiTECH (Chrysler/FCA Dealer Tool): Adaptation Drive Learn Procedure — After replacing the transmission, valve body/mechatronics unit, or clearing adaptation memory cells on an 8-speed (845RE, 8HP45, 8HP70) transmission. This procedure is necessary to relearn clutch fill times and pressures to ensure proper shift quality and prevent future codes.
• wiTECH (Chrysler/FCA Dealer Tool): Read Event Data — When diagnosing a P0733, the stored Event Data can show critical information like input RPM and the difference between desired and actual line pressure at the moment the fault occurred. This helps differentiate between a sensor/electrical issue (input RPM reads zero) and a hydraulic/mechanical issue (line pressure is low).
• wiTECH or advanced aftermarket scanner: Reset Adaptive Values / Quick Learn — After performing repairs like replacing a solenoid, valve body, or conductor plate, the learned values in the TCM must be reset. This forces the TCM to relearn clutch engagement points and pressures based on the new components, which is critical for proper operation.

Real Owner Repair Stories

• YouTube user '916 DEVO' (Chrysler 300s with NAG1 Transmission) — Vehicle in limp mode, speed sensor codes stored.
  ✅ What actually fixed it The conductor plate on the valve body was replaced using a comprehensive service kit. After replacement and clearing codes, the transmission control module showed no faults and the car was no longer in limp mode.
• BobIsTheOilGuy.com forum user (2009 Chrysler Aspen with 5.7L Hemi and 545RFE transmission) — P0733 code present. Shifts 1-2 fine, but will not shift from 2-3. Engine RPMs climb, then transmission feels like it's slipping and the vehicle coasts.
  ❌ Tried (didn't work) Fluid was not burnt and at the correct level. Scan tool showed line pressures were in spec.
  ✅ What actually fixed it The consensus from experienced forum members was that the Overdrive clutch pack was internally damaged ('smoked'), a common issue on RFE series transmissions that directly causes a failed 2-3 shift and the P0733 code.

OEM Part Supersession History

• 52108308AB → 52108308AC — This is the conductor plate for the 5-speed NAG1 (W5A580) transmission. Part revisions often address reliability issues or manufacturing improvements.
  Heads up: The new part number (52108308AC) is a direct replacement for the old one.

Model Year Variations Within This Range

• 2015-2019 (8-Speed ZF Transmissions): The solenoids in the ZF8HP series valve bodies are identified by letters (A, B, C, D, E, TCC, LPS). For Chrysler applications (845RE/ZF8HP45/70), the solenoids correspond to specific functions: SOL A, SOL B, SOL C, SOL D, SOL E, SOL TCC (Torque Converter Clutch), and SOL LPS (Line Pressure). Knowing which solenoid controls which clutch is critical for targeted diagnosis with a scan tool.