The same gen-four issues as 2016, quieter — brakes and the 8-speed lead, and the AC coverage still applied.

The 8-speed automatic shudders under light throttle and can shift harshly and hunt for gears, and in the file it can progress to torque-converter wear and a rebuild. GM's fix is a flush with a revised fluid spec, which quiets many trucks; a rebuild when that fails is a several-thousand-dollar job with no recall behind it. Test-drive specifically for a fine shudder at steady cruise and a firm 1–2 shift, and favor a truck with a documented transmission service.

The air-conditioning condenser can crack from thermal cycling and vent its refrigerant, disabling the AC. GM's Special Coverage (10207716 family) covered 2015–2017 Suburban and Tahoe with an inspect-and-replace for 5 years or 60,000 miles — a window most used 2017s have now passed. On a warm-climate truck, confirm the AC blows genuinely cold and ask whether the condenser has already been replaced; an out-of-coverage replacement runs into four figures.

The V8s' Active Fuel Management (AFM) deactivates cylinders to save fuel, and its collapsible lifters can stick or fail; a failed lifter scars the camshaft, so the repair is lifters plus a cam for several thousand dollars. It presents as a tick or tap, misfire codes, and lost power. There's no recall — a class action exists and GM repairs reactively. On the gen-four trucks it tends to surface later than on the gen-five DFM engines, but it's worth a cold-start listen and a look for a disabler tune.