The transmission year — the one third-gen Silverado where the 8-speed is the reason to walk unless it's been sorted.

The other expensive pattern. The 5.3L's cylinder-deactivation lifters can collapse, causing a tick, misfire, power loss, and often a bent pushrod and camshaft damage. Repair is $3,000–$10,000, and there's no recall — a class action alleges the defect while GM repairs reactively, so an out-of-warranty 2017 typically means owner-paid. Risk grows with mileage. An AFM disabler is cheap preventive insurance; a cold-start valvetrain tick is a warning to walk.

Some 5.3L and 6.2L trucks can develop a fuel-injector fault that makes the engine idle or run rough, stall, and throw a check-engine light. GM issued Special Coverage Adjustment N182198000 — but it only applies to vehicles in a specific list of emissions states (CA, CT, DE, ME, MD, MA, NJ, NY, OR, PA, RI, VT, WA). If the truck was sold or registered in one of those states, the injector repair may be covered; elsewhere it's owner-paid. Confirm eligibility by VIN.

Like the rest of the third generation, the 2017's A/C condenser can crack and leak with no recall behind it, running about $1,000 out of pocket; compressors fail too. Run the A/C cold on a warm day, and look for the upgraded-condenser mark in the top-right corner as a sign it's already been replaced.

The mechanical vacuum pump behind the brake booster can lose output over time, giving a hard pedal and longer stops — covered by recall 19V645 and a related GM Special Coverage for 2014/2017/2018 trucks. A firm pedal and a 'Service brake assist' message are the tells; verify by VIN the recall/coverage work was done.