If you've ever scanned your GM truck's build sheet and noticed transmission codes like MQB, MQC, MHT, MHS, or MI2, you may have wondered what they actually mean. While they're all part of GM's 10-speed transmission family, these RPO codes identify different calibrations, shifter configurations, and applications. Here's what each code means, which trucks use them, and why the 3.0L Duramax has its own dedicated transmission variants.

A teardown of a failed 7,500-mile LZ0 Duramax engine uncovered evidence suggesting only one thrust bearing may have been present. While this is only a single engine, the findings could help explain the excessive crankshaft end play and engine failures being reported by owners. Here's what was discovered and why it matters.

GM says some 3.0L LZ0 Duramax trucks showing 419°F fuel temperature readings and multiple DTCs may actually have a faulty MAP/IAT sensor. Here’s what bulletin PIP6119 says and how to access the sensor. The video naturally supports this article because it already covers MAP sensor access and removal. https://youtu.be/f2uBXmtPPpw

They look identical at first glance, but swapping the wrong glow plug on your 3.0 Duramax can lead to serious — even engine-destroying — problems. Discover the key differences between LM2 (73G) and LZ0 (72G) glow plugs, including voltage requirements, control module changes, fragility warnings, proper testing methods, and must-follow installation tips to keep your diesel running strong.

GM has released new service information addressing a 3.0 Duramax condition where the engine idles normally but hesitates, loses power, or stalls during acceleration. The cause points to an internal restriction in the charge air cooler hose — a component critical to proper boost and airflow on both LM2 and LZ0 engines.

GM bulletin PIT5689M addresses no-restart after Auto Stop, intermittent no-crank, dead battery, glow plug faults, transfer case errors, and multiple warning lights on Silverado and Sierra trucks. The root cause is often a loose or damaged engine-to-body ground at the passenger-side firewall (G132/G134). Inspecting and securing this ground can prevent widespread electrical faults and unnecessary parts replacement.

GM bulletin 25-NA-307 (LZ0 3.0 Duramax, 2025–2026) links bellhousing-area noise + MIL/P06DD to excessive crankshaft end play (possible thrust-bearing failure). Dealers should measure end play at the crank pulley bolt with a dial indicator; spec is 0.084–0.316 mm (0.0033–0.0124 in). Expect to pay diagnostic time for the check; if out of spec, repairs proceed per SI.

You’ve seen the window sticker. You’ve read the marketing. And if you’re like me, you’ve probably asked yourself: “Okay, but can this...

P2C7A on the 3.0 Duramax means the SCR/NOx catalyst isn’t meeting efficiency. Learn the real causes, exact diagnostics, and fixes for LM2/LZ0.

For Duramax diesel owners, the fuel system is the lifeline of your vehicle’s performance, delivering the power and efficiency you rely...

For many 3.0L Duramax owners, especially those with 2023+ LZ0 models who frequently tow, a new and deeply frustrating phenomenon is...

If you’re a 3.0 Duramax Diesel owner, you’ve likely heard of the P04FB code—it’s one of the most common diagnostic trouble codes (DTCs)...

A new ECM Calibration Update has just arrived. This update is available if you have one of these codes listed below, DO NOT GO TO YOUR...

A technical service bulletin #22-NA-128 addressing a malfunction indicator lamp (MIL) illumination issue has been updated to now include...

In modern diesel fuel systems, small quantity adjustment plays a crucial role in optimizing engine performance and fuel efficiency. Small...

Understanding Exhaust Regeneration in Your Chevrolet Silverado with a 3.0 Duramax Diesel Engine If you're a new owner of a Chevrolet...