2020 Chevrolet Tahoe: What to check before buying

A "service trailer brake system" warning that comes on by itself is the most common complaint, often with alarm tones. It appears even on trucks that never towed a braked trailer, and one report puts it near 60,000 miles. The backup camera shows blurry striped lines, then a blue "service rear vision system" screen. Other reports describe keyless entry missing the fob and locking keys inside, and StabiliTrak alerts with lost steering and brake assist below 5 mph. In one case the auxiliary battery exploded. A GM service bulletin covers relay overheating that melts its terminals.

Most of these complaints describe the transmission, not the engine. At 55 to 65 mph, RPMs jump and the truck feels like it is in neutral. Others drop into first gear on the expressway, which nearly caused a rear-end collision. Reverse can hesitate or fail to engage afterward. Owners cite an existing transmission recall and want it widened, and one faced a bill over $7000. Separate reports describe engine failures: an engine that seized soon after purchase, a broken piston, and a cylinder 1 misfire with white exhaust smoke. Oil pan and rear main seal leaks appear at 85,000 miles.

Transmissions fail suddenly. RPMs rise but the truck barely moves or stops dead in traffic, often with no warning light. Two reports put this near 100,000 miles, and one replacement cost $5500. Other signs include a high-pitched whine between 2nd and 3rd gear, dark gritty fluid, and metal shavings in the filter. One truck under 10,000 miles had clicking front hubs that shed metal shavings and needed replacement. Another complaint describes lifter ticking from the valve covers.

Power steering assist cuts out without warning, often at low speed or at a stop, and the wheel turns very stiff. Some trucks recover after a restart. One shows a "steering assist" message along with lost acceleration and a check engine light that the dealer could not reproduce. Rack-and-pinion failures appear between about 43,000 and 60,000 miles, either as creaking and groaning or a wheel that suddenly goes firm. One crash with 6 injuries followed a steering wheel that locked while slowing for a U-turn.

Two crash reports say the air bags did not deploy in heavy frontal impacts that caused serious injuries, including a neck fracture. In one of those, a mechanic found a bent or broken air bag bracket at about 16,000 miles. Separately, a restraint system warning light flickers on and off and then stays lit. A software update did not fix it.

The brake pedal turns very hard and the truck does not slow as expected. A "Brake Assist" warning appears, and the app shows an antilock brake message. One report describes the inner faces of both front rotors flaking off in chunks at 35,500 miles while the outer faces stay smooth. Another describes a design concern with the power-adjustable pedals: the height gap between gas and brake can catch a shoe on the side of the brake pedal.

The engine stalls, shakes, or idles rough after a check engine light, sometimes with hard shifts and hesitation. One truck had all 8 fuel injectors and both fuel rails corroded and snapped, which left it undrivable. Another had a failed high-pressure fuel pump that put fuel in the oil, leaving it thin and smelling of gas. That owner notes the part was recalled on other vehicles for bad welds and raises a fire risk.

A rear tire came completely off the rim in a slow left turn, and the truck hit a house. The tires had fewer than 100 miles on them, and the pressure warning lit only after the tire came off. In another report, a rear tire kept losing air from multiple pinholes and could not be repaired at 15,000 miles.