2018 Chevrolet Suburban: What to check before buying

Transmissions fail suddenly, often with no warning light. Reports describe hard or clunking shifts, slipping, shaking under acceleration, and abrupt loss of power in traffic or at highway speed, sometimes leaving the SUV stranded. Several shops blame the torque converter. Failures cluster between roughly 60,000 and 111,000 miles, with a few under 40,000, and one owner needed a second transmission. In one crash report, the shifter could be pulled out of Park with the engine off, and the vehicle rolled into a parked car. A few reports describe lifter or camshaft ticking.

The engine shuts off while driving. Sometimes it restarts on its own or after a key cycle, and sometimes the SUV needs a tow. Dealers trace several cases to overheated or faulty battery cables. Others go undiagnosed even after new batteries and ignition switches. Other reports describe no-start conditions, an instrument cluster that goes dark, and a Service Trailer Brake System warning tied to wiring. That wiring fault also lights StabiliTrak and ABS warnings, even on trucks that never tow. Intermittent stability-control lights can disable cruise control and steering assist.

Power steering assist cuts out without warning, often during low-speed turns, leaving the wheel very hard to turn. Some cases come with a full electrical shutdown or a string of warnings for the trailer brake system, ABS, and traction control. That points to the same wiring and voltage faults seen in electrical complaints. Owners describe near-collisions at intersections. One report describes an upper control arm breaking during a slow turn and the wheel tearing away, with some replacement parts no longer available.

Valve lifters fail, causing ticking or rattling, rough idle, misfires, and in some cases a sudden loss of power on the road. Dealers call it a known issue that can also damage the camshaft. No recall covers it, and repair quotes run to several thousand dollars. One lifter failure came after 60000 miles. Some owners link the problem to Active Fuel Management. Other reports describe stalls dealers cannot duplicate, a failed fuel injector, and a water pump that blew and dumped coolant.

Second-row seat belt retractors stop retracting or locking, often on the captain's chairs. That leaves the seat unusable and makes it hard to secure a child seat. Several owners report both second-row belts failing. Warning signs include slow retraction and loud clicking before the belt quits. One dealer blamed child car seat use. Owners outside warranty pay for the repair, with estimates around $500 or more. One report describes a rear center belt that will not extend.

The brake pedal turns hard and is nearly impossible to press, which sharply cuts stopping power. It happens at highway speed and in reverse. A brake assist message, the ABS light, or a Hill Descent Assist disabled message may appear. In some cases dealers replaced the vacuum pump, then the brake booster when the problem returned. One booster failure came at about 39,000 miles. Owners describe pulling onto the shoulder or standing on the pedal to stop.

Front-end crashes end with no deployment in two reports, which together list 4 people injured. One of those crashes happened at about 4,700 miles. Another owner reports a driver warning light traced to the overhead airbag, with the repair waiting on parts. In a separate case, a buyer who purchased from a private third party found that no air bags were installed, and the DMV refused to register the vehicle.

Problems center on the capless fuel filler. On one nearly new vehicle, the filler neck was replaced because a missing O-ring kept the fuel tank from pressurizing and triggered a fault code. In another case, the filler's automatic flap broke shortly after purchase. Neither report mentions a fire, a leak, or a loss of power. Both read as nuisance failures rather than safety risks.