GM Issues New Valve-Body Repair for P0747 on 10-Speed (10L80/10L90)

Published: September 23, 2025 • By: Greg Nelson

GM has released # 25-NA-255 (Sept 22, 2025) directing technicians to repair—not replace—the valve body when DTC P0747 (Transmission Control Solenoid Valve 1 Stuck On) triggers a default mode (5th gear only + Reverse) on certain 2021–2024 GM trucks and SUVs, including Silverado/Sierra 1500 with LM2/LZ0. The new fix replaces three components inside the control valve body:

• Feed Limit Low Valve (new steel design)

• Feed Limit Valve Spring (higher tension)

• Valve Body Spacer Plate (with gasket)

GM notes: apply this bulletin only on units with ≥7,000 miles, and do not use it if there’s excessive clutch debris in the pan. No SFL or MCVM re-characterization is required after the repair. ( Bulletin # 25-NA-255)

What changed (and why this matters)

Repair vs. Replace: Earlier guidance and coverage programs typically replaced the entire control valve body when P0747 was present. Now, GM has isolated a primary failure path to the Feed Limit Low valve and is standardizing an in-house repair with updated hardware, reducing costs and downtime while addressing durability (aluminum valve → steel valve + stronger spring). This aligns with independent technical analysis that has long pointed to feed-limit valve wear as the root cause of P0747, harsh shifts, limp-mode (5th-gear-only), and even the wheel-lockup hazard that triggered recalls and special coverages. (Sonnax)

Affected vehicles (high level)

• Chevrolet/GMC 1500 trucks (select 2021–2024, LM2/LZ0) and full-size SUVs (Escalade/Tahoe/Suburban/Yukon) with 10-speed transmissions (MQB/MQC/MHS/MHT/MHU/MI2/MHO, as applicable). Always confirm by VIN in IVH and EPC.

  
  

The new service action (shop overview)

• Disassemble valve body (ETRS vs. shift-by-cable details apply).

• Install three parts together: updated Feed Limit Low Valve, Spring, and Spacer Plate (w/ gasket).

• Preserve check-ball locations; reuse the thick plate gasket if undamaged.

• Torque most valve-body fasteners to 80 in-lb (9 N·m) where specified.

• No SFL / MCVM programming required after reassembly.

• Training: GM video Course 57530.06V accompanies the bulletin.(Procedural specifics from Bulletin # 25-NA-255)

Key diesel (LM2/LZ0) part examples (verify by VIN/EPC):

• Spacer Plate Assy (w/ gasket): 24075088 (MQB Diesel), 24075090 (MQC Diesel)

• Feed Limit Valve: 24059372 • Spring: 24279142

  
  

Aftermarket Solutions Came First

Before GM’s new bulletin, companies like Next Gen Drivetrain were already addressing the P0747 problem head-on. In a February 2025 article, they explained that the solenoids themselves almost never fail; instead, the real culprits are:

• Solenoid regulator valves that don’t return to a closed position because of bore wear and oil balance issues.

• Feed limit valves that wear at the spring pedestal, causing pressure leaks and delayed response.

Next Gen engineered feed limit valves with sealing rings and offered DIY upgrade kits or remanufactured valve bodies well before GM published its own official procedure. In effect, the aftermarket identified the root cause and developed a solution months earlier — GM’s new fix (#25-NA-255) now validates that approach by making it the official repair path.

Attribution: Information on early aftermarket solutions for P0747 sourced from “Diagnosed & Fixed: P0747 Code in General Motors 10-Speed Transmissions” by Nathaniel Valentin, Next Gen Drivetrain (Feb 6, 2025).

How GM handled this before (timeline & context)

1) Aug 2023 – Diagnostic/repair matrix (21-NA-169):GM’s drivability bulletin grouped solenoid DTCs. For P0747 specifically, if fluid condition was OK, the instruction was to replace both the solenoid body and the valve body (and inspect clutches if burnt/dark). This positioned P0747 as a case where full assemblies often went in. (NHTSA)

2) Nov–Dec 2024 – Safety Recall N242454440 (Momentary Rear Wheel Lock-Up) & FAQ:GM rolled out a software update to monitor the wearing valve and lock the transmission to 5th gear once excess wear was detected—intended to prevent the rare but hazardous wheel lock during an 8→2 downshift event. Owners began receiving notices in December 2024. (AP News)

3) Jan 27, 2025 – Special Coverage N242454441-02:When wear was confirmed (including P0747), GM instructed dealers to replace the complete control valve body and perform solenoid characterization programming, extending coverage to 15 years/150,000 miles for the condition.

4) Mar 2025 – Safety Recall N242480630 (expanded models):GM broadened the safety campaign (10L1000 + Gen-2 10L60/80/90). The official remedy phase focused on software detection and default-to-5th as a safety backstop (no parts required in the recall itself), while separate coverage handled hardware replacement if codes/conditions appeared. (NHTSA)

5) Sept 22, 2025 – New TSB # 25-NA-255:GM now formalizes an on-bench repair of the control valve body—steel Feed Limit Low valve + higher-rate spring + spacer plate—instead of routine full assembly replacement.

Independent technical sources (transmission engineering/rebuilder community) have documented feed-limit-valve side-load wear as the root cause behind P0747, limp-mode, and wheel-lock complaints, and have marketed dedicated Feed Limit Low Valve kits since before GM’s new TSB—useful for understanding the failure physics behind GM’s updated approach. (Sonnax)

What this means for owners and shops

For owners:

• If you get P0747 and the truck is stuck in 5th-only + Reverse, it’s a known pattern. Under prior programs, dealers often installed a new valve body; today, GM’s newest bulletin has dealers repairing the original valve body with updated internals. Warranty applicability varies by VIN/coverage; dealers must check IVH.

For service writers/techs:

• Screen for mileage (≥7,000 mi requirement) and pan debris (if excessive, follow SI—not this TSB).

• If eligible, use the three-part update. No SFL/MCVM needed; follow torque and ETRS vs. cable specifics.

  
  

FAQ

Is this the “newest fix” for valve-body issues causing P0747?Yes. Prior pathways frequently replaced the entire valve body (and sometimes solenoid body); GM’s # 25-NA-255 moves to a targeted internal repair with updated parts. (NHTSA)

How does this tie to the wheel-lock recalls?The same wear mechanism in the control valve can progress to hazardous behavior. GM’s recalls added software detection and 5th-gear defaulting to prevent wheel lock. The new TSB addresses the hardware cause with an improved valve/spring/plate combo. (AP News)

Do independent kits exist?Yes; technical write-ups and kits targeting the Feed Limit Low valve have been available and explain the side-load wear failure mode (helpful background for techs). GM’s bulletin is the official OEM pathway for covered vehicles. (Sonnax)

Sources & references

• GM Special Coverage N242454441-02 (Jan 27, 2025): describes P0747 from worn control valve, directs control valve body replacement + solenoid characterization; 15 yr/150k coverage. (NHTSA PDF).

• GM Safety Recall N242454440 (Dec 2024 notices): software strategy to detect wear, limit to 5th and prevent wheel lock. (NHTSA PDF; AP coverage). (NHTSA)

• GM Safety Recall N242480630 (Mar 2025): expanded applications; software detection / default-to-5th; no parts in recall remedy. (NHTSA PDFs). (NHTSA)

• GM 21-NA-169 (Aug 2023): diagnostic matrix; for P0747, replace solenoid body + valve body if fluid OK (historical baseline). (NHTSA PDF). (NHTSA)

• Transmission engineering community on Feed Limit Low valve wear and P0747/lock-up failure physics. (Sonnax kits, technical explainer; Gears Magazine). (Sonnax)