2018 GMC Sierra 1500 Problems: 13 Issues Every Owner Should Know
2018 model year · 4,075+ owner reports · Updated July 2026
According to Au7o's analysis of 4,075+ owner reports, the 2018 GMC Sierra 1500 has 13 documented known issues, with 5 rated critical. The most serious are AFM/DFM Lifter Collapse and Failure ($4,000-$8,000 repair), 8-Speed/10-Speed Transmission Torque Converter Shudder ($150-$4,500 repair), Electronic Brake Control Module Failure ($150-$1,500 repair), P0016 — Crank/Cam Correlation Fault from Stretched Timing Chain on 5.3L AFM V8 ($150-$1,800 repair) and P0700 — Transmission Fault Flag from Failing 6L80/6L90 Internal TEHCM ($600-$2,500 repair). The most commonly reported issue is AFM/DFM Lifter Collapse and Failure with 1,250 owner reports. Across all issues with published estimates, repair costs range from $20 to $8,000. DIY maintenance guides at au7o.io.