P0776 on Chevrolet

Gen 5 Camaros with the 6L80/6L90 six-speed automatic commonly exhibit a 2-3 upshift 'flare' where engine RPM briefly rises before the gear engages, sometimes followed by a firm bump. GM issued bulletins calling a mild 2-3 slip/flare a 'normal characteristic,' but worsening flare typically indicates a real hydraulic leak, most often at the 3-5-Reverse clutch drum or clutch-regulator valve, and can throw pressure/ratio codes. Left unaddressed, slipping accelerates clutch wear.

Equinox models with the GM 6T70/6T75 six-speed automatic suffer shudder, harsh or delayed shifts, slipping, and loss of reverse. A common root cause is failure of the 3-5-reverse wave plate, which can crack and cause extreme shudder when reverse is engaged and eventual loss of drive. Overheated/degraded fluid that loses viscosity accelerates internal wear. Failures typically appear between roughly 60,000 and 150,000 miles. Owners report bucking when engaging gear, failure to shift out of 2nd, and inability to engage reverse.

Silverados with the Hydra-Matic 8L90 (and 8L45) 8-speed automatic are widely reported to hesitate, then shudder, jerk, clunk or 'hard shift' when changing gears — some owners describe a shift so violent it feels like being rear-ended, plus a torque-converter-clutch shudder that feels like driving over rumble strips. The root cause is internal friction/hydraulic issues and torque-converter-clutch micro-slip, often worsened by the original transmission fluid breaking down, sending metal shavings through the unit. GM issued 13+ TSBs and a fluid change (to Mobil 1 Synthetic LV ATF HP / DEXRON-ULV) as the primary remedy, and the defect is the subject of a certified class action covering 2015-2019 Silverado and other GM models. Very high search and complaint volume.