P0747 on 2017-2023 Chevrolet Silverado 1500: Causes, Fixes, and Valve Body Issues

What's Unique About the 2017-2023 Chevrolet SILVERADO 1500

The 2017-2023 Silverado 1500, spanning the end of the third generation (K2XX) and the start of the fourth (T1XX), uses 8-speed (8L90) and 10-speed (10L80) automatic transmissions that are known to have issues with their internal valve bodies. GM has acknowledged this problem through multiple Technical Service Bulletins (TSBs) and a special coverage program (N242454441), indicating a pattern of premature wear in the valve body assembly that leads directly to code P0747. Unlike a simple solenoid failure on other vehicles, on these trucks, the root cause is often mechanical wear within the valve body itself, specifically the aluminum feed limit valve wearing its bore. This makes a complete assembly replacement or a targeted internal valve repair the most common and durable fix.

Diagnostic Flowchart

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

Generation note: This range covers the third generation (2017-2018) and the fourth generation (2019-2023) of the Silverado 1500. Both generations, particularly those equipped with the 8-speed (8L90) and 10-speed (10L80) automatic transmissions, are susceptible to the valve body issues that cause code P0747.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on
• Transmission will not shift or is stuck in one gear (often 5th gear).
• Harsh, jerky, or delayed gear shifts.
• Drastic reduction in vehicle speed and 'Reduced Power' message on dash.
• Engine revs but the truck doesn't accelerate properly (transmission slipping).
• Vehicle won't move forward from a stop, then slams into gear.
• Transmission overheating.
• Shaking or shuddering during shifts.

Most Likely Causes

1. Faulty Transmission Control Valve Body Assembly 🔴 High Probability → Shop Transmission Valve Body As documented in multiple GM TSBs (#24-NA-088, #N242454441), these transmissions suffer from premature wear within the valve body, specifically with the aluminum Feed Limit Low Valve and its bore. This wear creates a hydraulic leak, preventing proper pressure regulation and causing the solenoid circuit to register as 'stuck on'. Aftermarket companies like Sonnax and Next Gen Drivetrain identified this specific failure mode before GM issued its updated repair procedures.
   How to confirm: A professional diagnosis involving a transmission pressure test is the definitive method. However, given the number of TSBs and the Special Coverage Program, the presence of P0747 (sometimes with P0796) is a very strong indicator of valve body failure. A technician may also drop the pan to inspect for excessive clutch material, which would indicate a more severe failure requiring a full rebuild.
   Typical fix: Replacement of the entire transmission control valve body assembly is the most common fix. For some 2021-2024 models with the 10-speed transmission, GM issued TSB #25-NA-255, which directs dealers to perform an in-vehicle repair by installing an updated steel Feed Limit Low Valve, a stronger spring, and a new spacer plate instead of replacing the whole unit. 🎬 See how GM's updated steel valve fixes the bore wear
   Est. part cost: $400-$900
2. Low or Contaminated Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly While not specific to this platform, low or dirty fluid can cause erratic hydraulic pressure and solenoid issues in any automatic transmission. However, on these trucks, contaminated fluid (black, burnt, with metal shavings) is more often a *symptom* of the valve body failure causing clutch damage, rather than the root cause.
   How to confirm: Check the transmission fluid level and condition. The fluid should be at the correct level, red in color, and free of excessive debris or a burnt smell. TSB #24-NA-088 provides visual guides for what is considered normal fluid darkening versus fluid indicating severe distress.
   Typical fix: Perform a transmission fluid and filter change. If the fluid is heavily contaminated, it is a strong sign of mechanical damage, and simply changing the fluid will not solve the P0747 code.
   Est. part cost: $75-$150

Rare But Worth Checking

• Wiring Harness Damage: The wiring to the transmission can be damaged by road debris or heat, causing a short or open circuit to the pressure control solenoid. One owner reported transmission fluid wicking into the wiring harness, causing intermittent issues. GM has also issued TSBs (e.g., PIP5700E) regarding the internal transmission wiring harness, indicating it can be a point of failure requiring replacement. This should be inspected before condemning the expensive valve body.
• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly In rare instances, the TCM itself can fail, sending an incorrect signal to the solenoid. However, this is much less common than the mechanical valve body failure on these trucks. An early TSB for 2017 models (#16-NA-404) did involve a TCM software update to fix a calibration anomaly that could cause P0747, so checking for the latest software is a valid diagnostic step.
🎬 Watch: How to perform a transmission fast learn after repairs

Diagnosis Steps

1. Verify the code P0747 is present using an OBD-II scanner. Note any other codes, such as P0796 or P0700.
2. Check the transmission fluid level and condition. Ensure it is full and not burnt or contaminated with excessive metal debris. Compare fluid condition to GM's TSB images if possible.
3. Inspect the transmission wiring harness and connectors for any visible signs of damage, corrosion, or loose connections. Check for fluid intrusion into the harness.
4. Using an advanced scan tool, check for any available TCM software updates. An early TSB for 2017 models addressed this code with a re-flash.
5. If fluid and wiring are okay, a technician will use an advanced scan tool to command the solenoid on and off while monitoring transmission pressure data to see if it responds correctly.
6. Perform a hydraulic pressure test to confirm if the pressure is out of specification, which points to an internal leak or a stuck valve.
7. Based on the numerous TSBs for this vehicle, if the above steps do not reveal a simple cause, the valve body is the primary suspect. Check the vehicle's VIN in the GM system to see if it qualifies for Special Coverage N242454441.

Parts You'll Likely Need

• Automatic Transmission Control Valve Body (OEM #24297642 (newer), 24275873 (older)) — This is the most common failure point for code P0747 on this vehicle, as confirmed by multiple manufacturer TSBs. The assembly contains the solenoids and valves that fail due to wear in the valve bores. Part number 24275873 is an older version, while newer replacements may have different numbers like 24297642.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $500-$1400
  Aftermarket price range: $400-$700
• Feed Limit Low Valve Kit (OEM #N/A (Included in TSB #25-NA-255)) — For 2021-2024 10-speed models, TSB #25-NA-255 specifies a repair using an updated steel valve, spring, and spacer plate instead of a full valve body replacement. Aftermarket companies like Sonnax also sell upgraded valve kits (e.g., 105740-54K) to address the root cause of the bore wear.
  Trusted brands: Sonnax, Next Gen Drivetrain
  OEM price range: N/A (Dealer part)
  Aftermarket price range: $50-$150

Related Codes That Often Appear With This One

• P0796 — TSB #PIP5425A specifically notes that P0796 (Pressure Control Solenoid 'C' Performance/Stuck Off) can appear alongside P0747. Both solenoids are located in the same valve body assembly, and a widespread internal hydraulic issue or contamination can affect multiple solenoid circuits.
• P0700 — This is a generic Transmission Control System Malfunction code. The TCM sets this code to inform the main Engine Control Module (ECM) that a transmission-specific fault has occurred, triggering the Check Engine Light. P0700 will almost always be present when a specific transmission code like P0747 is stored.

Technical Service Bulletins (TSBs) & Recalls

• 24-NA-088: Mentions replacing transmission control valve bodies to correct MIL illumination and P0747. Provides visual examples of fluid condition.
• N242454441-03: Describes a gradual loss of pressure within the valve causing harsh shifting and P0747. This is a Special Coverage program that instructs dealers to install a new control valve body at no charge for 15 years/150,000 miles.
• PIP5425A: An early bulletin for the 2017 model year noting that engineering was investigating a solution for P0747 and P0796.
• 25-NA-255: A newer bulletin for 10-speed transmissions (2021-2024) directing technicians to repair the valve body with an updated internal steel feed limit valve kit instead of replacing the entire assembly.
• 16-NA-404: An early TSB for 2017 models that addressed P0747 and other codes with a TCM software reprogram due to a calibration anomaly.

Platform-Specific Known Issues

• GM has issued multiple Technical Service Bulletins (TSBs) related to P0747 on these trucks. TSB #24-NA-088 and Special Coverage #N242454441 directly call for the repl

Mechanic-Grade Diagnostic Values

• Pressure Control (PC) Solenoid Resistance (8L90) — expected: 4.5–5.5 ohms. Failure: A reading outside this range indicates a faulty solenoid coil.
• Transmission Fluid Temperature for Fast Learn Procedure — expected: 167°F (75°C) to 185°F (85°C). Failure: The scan tool will not initiate the 'Transmission Service Fast Learn' procedure if the fluid temperature is outside this range.
• Line Pressure at Idle in Drive (8L90) — expected: 55-60 psi minimum. Failure: Pressure below this range could indicate a worn valve body, pump issue, or major leak.

Scan Tool Commands That Help

• GDS2 / High-End Scan Tool (Autel, Snap-on): Transmission Service Fast Learn — This procedure must be performed after replacing the valve body, TCM, or entire transmission. It allows the TCM to learn the individual clutch apply pressures and characteristics to ensure proper shift quality. Failure to perform this can result in harsh or erratic shifting.
• GDS2 (GM Dealer Tool): MCVM (Mechanical Characterization and Virtual Matching) Operations — When replacing a transmission, valve body, or individual solenoids, the unique performance data (PUN/TUN) for the new components must be programmed into the TCM. This function downloads the correct characterization data from GM's server (TIS2Web) and writes it to the module.
• GDS2 (GM Dealer Tool): Solenoid Data Characterization — This is a specific function within the MCVM operations used to 'refresh' or update the solenoid performance data in the TCM after a component replacement, ensuring the TCM commands the solenoids correctly based on their unique flow rates.

Wiring & Ground Locations

• Main Transmission Electrical Connector (8L90) — On the passenger side of the transmission case.. This is the primary interface between the vehicle's main harness and the transmission's internal components, including all solenoids. A video guide on transmission removal shows a red locking tab that must be slid out before the connector can be unplugged. Damage, corrosion, or fluid intrusion at this connector can cause a wide range of transmission codes, including P0747.
• Internal Transmission Wiring Harness — Inside the transmission, connected to the valve body and solenoids.. GM has issued service bulletins (PIP5700E) with specific part numbers for replacing the internal two-piece wiring harness for the 8L90, as it has been identified as a failure point. A faulty internal harness can cause intermittent open or short circuits to the solenoids, mimicking a solenoid or valve body failure.

Real Owner Repair Stories

• Reddit user 'AllThemNinjas' (2017 Silverado 1500 6.2L with 8L90 transmission, 72k miles) — While stopped at a light, the check engine light came on. The truck would only rev and not move, then slammed into 1st gear and would not shift up. Code P0747 was retrieved.
  ❌ Tried (didn't work) The issue temporarily resolved itself after turning the truck off and on. The check engine light cleared after a few key cycles.
  ✅ What actually fixed it The user did not post a final mechanical fix, but another user with a 2019 8L90 reported that ignoring the intermittent symptom eventually led to a full transmission rebuild costing $6,000. This highlights the importance of addressing the issue early, even if it seems to disappear.
• Reddit user 'Cool-Grapefruit-4355' (2023 GMC Sierra AT4 with 33,000 miles) — Check engine light with code P0747.
  ✅ What actually fixed it The dealership diagnosed the issue and confirmed the fix was replacing the valve body. The part was in stock at their location, but they noted that many other dealerships were facing a 6 to 8-week national backorder for the part.

OEM Part Supersession History

• 24257213, 24041874 → 24275873 — Updated design to address internal wear and performance issues. These older numbers are often associated with earlier 6-speed and 8-speed valve bodies.
  Heads up: Part number 24275873 is listed for a wide range of GM vehicles, including some with the 6L90 transmission, and includes the TCM. It's critical to verify the correct part number for the specific vehicle's VIN and transmission (8L90 vs 10L80), as valve bodies are not interchangeable.
• N/A (Full Valve Body Replacement) → In-vehicle repair kit (Steel Feed Limit Low Valve, Spring, Spacer Plate) — GM identified the specific root cause in the 10-speed (10L80) as wear at the Feed Limit Low valve. TSB #25-NA-255 introduced a more targeted and cost-effective repair that replaces the worn components instead of the entire valve body assembly.
  Heads up: This repair procedure is specifically for certain 2021-2024 models with the 10-speed transmission and should not be applied to vehicles with the 8-speed (8L90) or if there is excessive clutch debris in the pan.

Model Year Variations Within This Range

• 2017-2023 (8L90 Transmission): These models are primarily affected by the general valve body wear issues. The common fix is a complete valve body replacement and requires a 'Transmission Service Fast Learn' and 'Solenoid Characterization' programming with a GDS2 or equivalent scan tool.
• 2021-2023 (10L80 Transmission): For these models, GM issued TSB #25-NA-255, which provides an in-vehicle repair procedure. Instead of replacing the entire valve body, technicians are instructed to install an updated steel Feed Limit Low Valve, a new spring, and a spacer plate. This specific repair does NOT require the solenoid characterization programming afterward.