P0740 on 2014-2020 Ram 3500: TCC Out of Range Causes and Fixes

What's Unique About the 2014-2020 Ram 3500

For the heavy-duty Ram 3500, equipped with robust transmissions like the Chrysler 68RFE or the Aisin AS69RC, P0740 is less often a simple electrical issue and more commonly a sign of internal mechanical or hydraulic failure. Manufacturer technical service bulletins confirm that if the TCC solenoid is functioning, this code is a strong indicator of torque converter failure. [TSB #9004009] The code is also frequently seen with P0868 (Line Pressure Low), especially on 68RFE-equipped trucks, pointing to a broader hydraulic problem within the transmission. 🎬 Watch: Expert breakdown of 68RFE valve body failures and fixes. [TSB #1806623, #1810122REVA, #18-101-22, #1805920] For the Aisin AS69RC, individual solenoids are often not sold by the dealer, sometimes requiring a full valve body replacement to fix a solenoid issue. However, individual solenoids are becoming available in the aftermarket.

Diagnostic Flowchart

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

Generation note: This year range covers the end of the fourth generation (2014-2018) and the beginning of the fifth generation (2019-2020) Ram 3500. The primary transmissions, the 68RFE and Aisin AS69RC, were used across these years, and the P0740 issue is common to both generations. TSBs related to this code have been issued for model years in both generations. For the 68RFE, valve body and software changes were implemented for the 2019 model year, which may affect diagnostics and part selection.

Symptoms You May Notice

• Check Engine Light (MIL) is on
• Vehicle jerking or slipping, especially at highway speeds. [TSB #9004009]
• Engine RPMs are higher than normal at cruising speeds.
• Noticeable decrease in fuel economy.
• Inability for the Multi-Displacement System (MDS) or 'ECO' mode to activate.
• Shuddering or stalling, especially during lock-up.
• Transmission overheating, particularly when towing or on long trips.

Most Likely Causes

1. Failed Torque Converter 🔴 High Probability → Shop Automatic Transmission Torque Converter A manufacturer TSB explicitly states that if the TCC solenoid is functional, P0740 is indicative of torque converter failure. [TSB #9004009] Forum discussions and mechanic reports confirm this is the most common failure point, especially if P0740 is the only code present. The stock converters in both the 68RFE and Aisin AS69RC are known weak points under heavy use.
   How to confirm: After confirming the TCC solenoid is working via a scan tool, the presence of metallic debris in the transmission pan is a strong sign of converter failure. A definitive diagnosis often requires transmission removal and inspection. A pressure test showing low TCC apply pressure can also point to an internal leak, often from the converter.
   Typical fix: Replace the torque converter. This requires removing the transmission from the vehicle. Many owners opt for a heavy-duty aftermarket converter from brands like BD Diesel, SunCoast, or Revmax for improved durability.
   Est. part cost: $400-$1800
2. Faulty Torque Converter Clutch (TCC) Solenoid 🟡 Medium Probability → Shop Automatic Transmission Torque Converter The TCC solenoid (also called L/R solenoid on 68RFE) controls the hydraulic pressure that engages the clutch. It can fail electrically or become stuck. TSBs recommend checking its operation first. [TSB #9004009] However, replacing it alone may not fix the issue if debris from a failing converter has contaminated the valve body.
   How to confirm: Use a bidirectional scan tool to command the TCC solenoid on and off while monitoring transmission data. A lack of response or an audible click indicates a faulty solenoid or wiring issue. Resistance checks can also be performed on the solenoid circuit; for the 68RFE L/R solenoid, the expected resistance is approximately 1.3 to 1.8 Ohms.
   Typical fix: Replace the TCC solenoid, which is located inside the transmission, often as part of the valve body or a solenoid pack. On Aisin AS69RC transmissions, the solenoid may not be available separately from the dealer, requiring valve body replacement. For 2019+ 68RFE models, the TCC solenoid is a different part number (e.g., 68456067AA) than earlier models.
   Est. part cost: $55-$550
3. Low or Contaminated Transmission Fluid 🟡 Medium Probability → Shop Transmission Assembly Heavy-duty use can degrade fluid faster. Low fluid levels or fluid contaminated with clutch material or metal shavings can prevent proper hydraulic operation and cause solenoids to stick.
   How to confirm: Check the transmission fluid level and condition. The fluid should be at the correct level, red in color (for ATF+4) or the specific Aisin fluid color, and free of burnt smells or debris.
   Typical fix: Perform a transmission fluid and filter change. If the fluid is heavily contaminated, a full flush may be needed, but this can sometimes worsen issues in high-mileage transmissions. A fluid change is often the first attempted fix but rarely solves the root mechanical problem.
   Est. part cost: $50-$350
4. Worn Valve Body or Transmission Pump ⚪ Low Probability → Shop Transmission Assembly On 68RFE transmissions, wear in the valve body's solenoid switch valve bore or the pump's TCC accumulator piston bore can cause hydraulic leaks that prevent the TCC from applying correctly. This is a well-documented failure mode, and aftermarket solutions exist to repair these worn bores without replacing the entire assembly.
   How to confirm: This requires transmission disassembly and inspection of the valve body and pump assembly for wear and sticking valves. Vacuum testing the bores is a common professional diagnostic technique; a worn TCC accumulator bore will fail to hold the recommended minimum of 18 in-Hg.
   Typical fix: Repairing the worn bores with aftermarket kits (e.g., Sonnax TCC Accumulator Valve Kit 44912-18K for pre-2019 models or Accumulator Piston Kit) or replacing the valve body and/or transmission pump assembly.
   Est. part cost: $500-$1500

Rare But Worth Checking

• Outdated PCM/TCM Software: In some cases, particularly on 6.4L Hemi models with the 66RFE transmission, a PCM/TCM software update has been documented to resolve the P0740 code. It's worth checking with a dealer for available updates (like TSB 21-010-16) before performing expensive mechanical repairs.
• Wiring Harness Issue: Damage to the wiring between the PCM/TCM and the transmission can cause an electrical fault, though this is less common than mechanical failures for this specific code on this truck. Check for chafing, corrosion, or loose connections at the main transmission connector.

Diagnosis Steps

1. Check and verify the transmission fluid level and condition. Note any burnt smell or discoloration.
2. Use a professional OBD-II scanner to check for any other transmission-related trouble codes, paying close attention to P0868 and P2764.
3. Check with a Ram dealership to see if there are any open recalls or available PCM/TCM software updates for your vehicle's VIN, especially for 6.4L Hemi models.
4. Using a bidirectional scan tool, monitor the Torque Converter Clutch slip RPM in real-time during a test drive. Excessive slip (over 100 RPM) when lock-up is commanded confirms the fault.
5. Command the TCC solenoid on and off with the scan tool to test its electrical function and listen for an audible click.
6. Perform hydraulic pressure tests on the TCC apply and release ports if possible. Low apply pressure indicates an internal leak. A high release pressure (over 5 psi) can also indicate a problem.
7. Drop the transmission pan and inspect for excessive metal shavings or clutch material, which indicates internal mechanical failure (likely the torque converter).
8. If the solenoid tests bad and the pan is clean, replace the TCC solenoid.
9. If the solenoid tests good but slip is present and/or debris is found in the pan, the torque converter is the primary suspect and likely needs replacement.
10. If the converter is replaced and the issue persists, or if no debris is found, inspect the valve body and pump for worn bores.

Parts You'll Likely Need

• Torque Converter (OEM #68RFE: R8419671AH (supersedes R8119671AG, R8419671AG); Aisin AS69RC: 68335702AA (supersedes RL335702AA, 68214649AA/AB)) — This is the most common point of failure for code P0740 on these trucks, as confirmed by manufacturer TSBs and field data. [TSB #9004009, 17, 19]
  Trusted brands: Mopar, BD Diesel, SunCoast

Related Codes That Often Appear With This One

• P0868 — This code for 'Line Pressure Low' is frequently cited alongside P0740 in Ram TSBs, especially for the 68RFE transmission, indicating a widespread hydraulic pressure issue. [TSB #1806623, #1810122REVA, #18-101-22, #1805920]
• P2764 — This code for the TCC Pressure Control Solenoid Control Circuit is also mentioned with P0740 in a TSB, pointing directly to an issue in the TCC's hydraulic control system. [TSB #9004009]
• P0700 — This is a generic Transmission Control System Malfunction code. It simply means the TCM has stored a fault code (like P0740) and has requested the MIL to be turned on. It will almost always appear with P0740.

Technical Service Bulletins (TSBs) & Recalls

• 9004009: States that if the TCC solenoid is okay, P0740 indicates torque converter failure.
• 1806623: Lists P0740 'TCC Out Of Range' with other codes, including P0868 'Line Pressure Low' for the 68RFE transmission.
• 1810122REVA: Lists P0740 'TCC Out Of Range' with other codes, including P0868 'Line Pressure Low' for the 68RFE transmission.
• 18-101-22: Lists P0740 'TCC Out Of Range' with other codes, including P0868 'Line Pressure Low' for the 68RFE transmission.
• 1805920: Lists P0740 'TCC Out Of Range' with other codes, including P0868 'Line Pressure Low' for the 68RFE transmission.

Platform-Specific Known Issues

• Intermittent Nature of the Fault: Many owners report that the P0740 code can appear intermittently, sometimes only under specific conditions like cold weather or while towing. The check engine light may clear after restarting the vehicle, only to return later. This can make diagnosis challenging, as described by a user on RamForum.com whose code disappeared for a period before they considered a major repair.
• 6.4L Hemi PCM Reflash Fix: A notable exception to the common mechanical failures is found in some 6.4L Hemi trucks with the 66RFE/68RFE transmission. There are documented owner experiences, such as one on RamForum.com, where a dealership PCM software update completely resolved the P0740 code after a transmission service failed to do so. This should be a primary check for any Hemi owner with this code.
• Aisin AS69RC Valve Body vs. Solenoid: → Shop Transmission Valve Body For trucks equipped with the Aisin AS69RC, a P0740 code can be more complicated if the solenoid is suspected. As noted in forum discussions, Ram dealers often do not sell individual solenoids for the Aisin valve body. This means a confirmed solenoid failure could necessitate the replacement of the entire, more expensive, valve body assembly.

Mechanic-Grade Diagnostic Values

• 68RFE TCC (L/R) Solenoid Resistance — expected: 1.3 - 1.8 Ohms. Failure: An open circuit (infinite resistance) or a reading significantly outside this range.
• 68RFE Pressure Control Solenoid Resistance — expected: ~4.9 Ohms. Failure: A reading significantly different from the specification.
• Scan Tool TCC Slip RPM (at commanded lock-up) — expected: 0 +/- 20 RPM. Failure: Slippage greater than 100 RPM for 10 seconds will set the P0740 code.
• 68RFE TCC Apply Pressure (Damper Apply Port) — expected: Should match actual line pressure (approx. 120 psi). Failure: A low reading, such as 85 psi, indicates an internal hydraulic leak.
• 68RFE TCC Release Pressure (Damper Release Port) — expected: 5 psi or lower. Failure: A high reading, such as 20 psi, indicates a problem (like a stuck valve) preventing full clutch application.
• 68RFE Valve Body Vacuum Test (TCC Accumulator Bore) — expected: Should hold a minimum of 18 inches of Hg.. Failure: A rapid drop in vacuum indicates excessive wear in the valve bore, causing a hydraulic leak.

Scan Tool Commands That Help

• wiTECH or equivalent bidirectional scanner: TCC Solenoid Command (On/Off) — To test the electrical integrity and mechanical function of the TCC (L/R) solenoid. A lack of an audible click from the transmission or no change in data PIDs indicates a problem with the solenoid or its circuit.
• wiTECH or equivalent bidirectional scanner: Monitor 'TCC Slip Speed' PID — During a road test, this value should drop to near zero when the PCM commands lock-up. If slip remains high (e.g., >100 RPM) when lock-up is commanded, it confirms a mechanical or hydraulic failure in the TCC system.

Wiring & Ground Locations

• Transmission Solenoid / TRS Assembly Connector — On the driver's side of the transmission case.. This is the main electrical interface for all internal transmission solenoids. The TCC (L/R) Solenoid Control circuit is on Pin 2, and the shared power feed from the control relay is on Pin 10. Checking for corrosion, pushed-out pins, or damage here is a critical first step in diagnosing an electrical fault.

Real Owner Repair Stories

• RamForum.com user 'Tim Pederson SD' (2018 Ram 3500 with 6.4L Hemi, 77,000 miles) — Check Engine Light with code P0740. The only performance issue was that the MDS was disabled.
  ❌ Tried (didn't work) A transmission fluid flush and change temporarily cleared the code for about 1,000 miles., Adding Lucas Trans Fix after the code returned.
  ✅ What actually fixed it The dealer found a new software update for the PCM and reflashed it. The problem was resolved and did not return for at least 2,000 miles.
• Gears Magazine Tech Article (2016 Ram 2500 with 6.7L Diesel and 68RFE) — Transmission overheating (up to 230°F), vibration at highway speeds, and code P0740.
  ❌ Tried (didn't work) Initial fluid check was normal., Transmission cooler was tested and found to be working correctly.
  ✅ What actually fixed it Diagnosis found high TCC release pressure (20 psi instead of <5 psi). The transmission was removed and inspection revealed a worn solenoid switch valve in the valve body and a worn torque converter accumulator valve in the pump. Repairing these bores with aftermarket kits and installing a new torque converter resolved all issues.
• Reddit r/Cummins user report (2014 Ram 2500 Diesel, ~170,000 miles) — P0740 code, wouldn't shift into 5th or 6th. Later set P0841 and wouldn't shift out of park.
  ❌ Tried (didn't work) Changing transmission fluid and filters.
  ✅ What actually fixed it The consensus from experienced users was that the valve body was likely gone and the overdrive clutches were smoked, requiring a full transmission rebuild. One user with similar symptoms (losing overdrive, hard shifts) had the issue resolved with a PCM/TCM software update at the dealer, though the primary recommendation was a mechanical rebuild.

OEM Part Supersession History

• R8119671AG, R8419671AG → R8419671AH — Standard part revision and update by Mopar for the 68RFE torque converter.
• Pre-2019 68RFE TCC Solenoid (part of solenoid block) → 68456067AA (2019+ TCC VFS Solenoid) — The 2019+ 68RFE transmissions use an updated valve body and a different, individually replaceable Variable Force Solenoid (VFS) for TCC control.
  Heads up: The pre-2019 solenoid block and the 2019+ individual VFS solenoid are not interchangeable.

Model Year Variations Within This Range

• 2019-2020: The 68RFE transmission was updated for the fifth-generation Ram. It features a different valve body, revised software tuning for smoother shifts, and a new, separate TCC VFS solenoid (P/N 68456067AA) instead of it being integrated into the main solenoid block. Repair kits for worn valve body bores are also year-specific; for example, Sonnax kit 44912-18K fits pre-2019 models, while kit 92835-25K is for 2019-later units.
• 2011+: The OD solenoid was removed from the 68RFE valve body starting in the 2011 model year. While outside the primary vehicle range, this is a critical note for anyone sourcing used transmissions, as a 2011+ valve body will not work in a pre-2011 truck without reprogramming, and vice-versa.