GM Duramax LZ0 Engine Noise & Oil Pressure Alert (Short)

We are investigating potential issues affecting certain 2025–2026 General Motors vehicles equipped with the LZ0 3.0L Duramax diesel engine, including reports of mechanical noise, oil-pressure fault codes, and Check Engine Light illumination. If your vehicle is affected, you may contact us confidentially and free of charge. No lawsuit has been filed, and no class proceeding has been certified.

GM Duramax LZ0 Engine Investigation (Detailed)

Our firm is reviewing reports concerning certain 2025–2026 Chevrolet and GMC vehicles equipped with the LZ0 3.0L Duramax inline-six diesel engine. Owners have reported mechanical noise originating from the bellhousing area, recurring Check Engine Light warnings, and diagnostic trouble code P06DD (“Engine Oil Pressure Control Valve Performance”).

These concerns are addressed in General Motors Service Bulletin 25-NA-307, which identifies crankshaft end play—axial movement of the crankshaft beyond specified tolerances—as a potential cause of the reported symptoms. According to GM’s guidance, excessive end play may result from thrust bearing wear or internal clearance issues and can interfere with proper oil-pressure regulation.

Based on the information reviewed to date, excessive crankshaft end play may contribute to erratic oil-pressure control, recurring fault codes, and progressive internal engine damage. In some circumstances, if left unaddressed, continued operation under these conditions may increase the risk of severe or catastrophic engine failure, including damage to internal engine components. At this stage, no conclusions have been reached regarding the frequency or likelihood of such outcomes, and the investigation remains ongoing.

Potential Automotive Class Proceeding Under Investigation: GM LZ0 Duramax Crankshaft End Play and Oil-Pressure Issues (Main)

Our firm is currently investigating a potential multi-jurisdictional (Canada-wide) class proceeding in British Columbia involving the following vehicles equipped with the LZ0 3.0L Duramax diesel engine:

• Chevrolet Silverado 1500 (2025–2026)
• Chevrolet Suburban (2025–2026)
• Chevrolet Tahoe (2025–2026)
• GMC Sierra 1500 (2025–2026)
• GMC Yukon (2025–2026)
• GMC Yukon XL (2025–2026)

GM Service Bulletin 25-NA-307 confirms that excessive crankshaft end play can produce mechanical noise and trigger DTC P06DD. The bulletin directs technicians to measure crankshaft movement using a dial indicator, with acceptable tolerances specified as 0.084–0.316 mm (0.0033–0.0124 inches). If measurements exceed these limits, dealers are instructed to inspect and repair the crankshaft thrust bearing and related components.

While the bulletin reflects manufacturer acknowledgment of a potential internal engine condition, it is not a recall, and owners are not proactively notified. The bulletin is accessible only through GM’s dealership service network.

This investigation is ongoing and is being conducted to assess whether the legal requirements under British Columbia’s Class Proceedings Act may be met, including whether common issues exist and whether a class proceeding would be the preferable procedure. No Notice of Civil Claim has been filed, and no class proceeding has been certified.

Owners who have experienced recurring noise, repeated fault codes, or multiple service visits without a lasting resolution may wish to ensure that repair documentation reflects whether the bulletin’s crankshaft end-play measurement procedure was performed.

This page will be updated as the investigation progresses.
This webpage is provided for informational purposes only and does not constitute legal advice.

Frequently Asked Questions – GM LZ0 Duramax Engine Investigation

What is the issue being investigated?
We are reviewing reports that certain vehicles equipped with the LZ0 3.0L Duramax engine may experience mechanical noise, oil-pressure fault codes (including P06DD), and Check Engine Light illumination, potentially associated with excessive crankshaft end play.

Has a class proceeding been filed?
No. At this time, no Notice of Civil Claim has been filed and no class proceeding has been certified.

What does “certification” mean?
Certification is a procedural step where the court determines whether a lawsuit may proceed as a class proceeding. It does not determine liability or damages.

Which vehicles may be affected?
Certain 2025–2026 Chevrolet Silverado 1500, Suburban, Tahoe, and GMC Sierra 1500, Yukon, and Yukon XL vehicles equipped with the LZ0 Duramax engine.

What does GM’s service bulletin say?
GM TSB 25-NA-307 instructs technicians to measure crankshaft end play using a dial indicator and to inspect and repair thrust bearing components if measurements exceed specified tolerances.

Can this issue cause serious engine damage?
Based on available information, excessive crankshaft end play may contribute to progressive internal engine damage and, if left unresolved, may increase the risk of severe or catastrophic engine failure in some circumstances. No conclusions have been reached regarding how often this may occur.

How can I provide information?
If you own or lease an affected vehicle and have experienced related symptoms, you may contact our firm confidentially and free of charge. Providing information does not obligate you to retain counsel or participate in any legal proceeding.

Will I automatically be included if a class proceeding is certified?
If a class proceeding is certified, individuals who fall within the class definition are typically included unless they choose to opt out, subject to the court’s order.