The GM 6L80 6-speed automatic powered Silverados, Tahoes, Camaros, and Corvettes for a decade. It is generally a tough box, but valve-body wear and solenoid-pack failures are nearly guaranteed somewhere between 100,000 and 180,000 miles.
Solid transmission overall but ages predictably. Valve body and solenoid pack issues are the most common high-mileage repair, typically $800-$1,500.
Slipping or flaring on the 1-2 shift is the classic 6L80 failure. Caused by worn 1-2-3-4 clutches and valve-body bore wear. Often paired with a P0776 code.
View P0776 Diagnosis →Aluminum valve body bores wear out around the pressure regulator and TCC valves. Causes inconsistent shift quality, slip, and torque-converter shudder.
View P0700 Diagnosis →Pressure-control and shift solenoids fail or get stuck. Symptoms range from harsh shifts to limp mode. Often replaced as a complete pack.
View P0750 Diagnosis →TCC shudder under light load - similar feel to the 8L90 issue. Cause is converter clutch wear; fix is a converter replacement.
View P0741 Diagnosis →Plastic radiator-side cooler-line connectors crack with age. Drops red ATF on the driveway.
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2007-2009 early 6L80 builds had the highest valve body issues. Avoid trucks over 180K with no transmission service history.
2012-2015 6L80 builds with documented fluid changes. Many enthusiasts also recommend the 6L90 (heavier-duty version) over the 6L80 in HD trucks.
Routine fluid + filter every 50K-60K runs $250-$400. A solenoid pack replacement around 130K is typical at $800-$1,200. A full valve body or rebuild is $2,000-$3,500. Lifetime non-routine spend: $1,500-$3,500.
If your 6L80 is throwing a check engine light, these are the codes most often associated with the problems above. Click any code for full diagnosis steps and typical repair costs.
150,000-200,000 miles with regular fluid changes is typical. The first major service (solenoid pack or valve body) usually comes around 130K.
Dexron VI or a high-quality synthetic equivalent (Mobil 1 Synthetic LV ATF HP works well). Use only the spec'd fluid - the 6L80 is sensitive.
A full rebuild typically runs $2,500-$4,500 at a transmission shop. A reman unit installed is around $3,500-$5,000.
Most often worn 1-2-3-4 clutch packs and valve body bore wear. Sometimes you can buy time with a sonnax fix or shift kit, but a rebuild is usually coming.
2007-2017 Silverado, Sierra, Tahoe, Yukon, Suburban, Escalade, Camaro, Corvette C6 (some), Caprice PPV, and CTS.