P0742 on Chevrolet: How to Diagnose & Fix

Both the 8-speed and 10-speed automatic transmissions can develop a shudder during light acceleration. This torque converter clutch issue is widespread across GM trucks. Multiple TSBs have been issued addressing this concern.

The 8L45 8-speed automatic transmission can develop a shudder during light acceleration, typically between 25-50 mph. This is caused by torque converter clutch issues, similar to problems in other GM vehicles with this transmission family.

The 8L90 and 8L45 8-speed automatic transmissions experience torque converter clutch shudder, causing vibration and shaking during gear changes. The issue is caused by the lock-up clutch slipping and chattering. This defect has been the subject of class action lawsuits against GM.

Transmission shuddering is common in Equinox models, typically caused by torque converter clutch issues or depleted transmission fluid additives. The shudder is most noticeable during light acceleration between 25-50 mph as the transmission shifts through 3rd-5th gears.

The first-generation Cruze with the 6T40 automatic transmission develops a shudder during torque converter lockup in the 25-45 mph range. The torque converter clutch friction material wears and generates debris that contaminates the fluid, worsening the shudder over time in a vicious cycle. The shudder feels like driving over a textured road surface and is most noticeable during gentle acceleration. The 6T40 in the Cruze sees more stress than in larger vehicles because the 1.4T engine produces torque at low RPM, keeping the converter locked more often.

The C7 Corvette with the 7-speed manual or 8-speed automatic can develop an annoying driveline vibration/shudder at low speeds, particularly during gentle acceleration from a stop. The 7-speed manual uses a dual-mass flywheel that can develop chatter. The 8-speed automatic (8L90) shares the torque converter shudder issue with GM trucks. The transaxle-mounted differential and half-shafts can also contribute to vibrations.

Same 8L90 torque converter shudder as Tahoe/Silverado/Escalade. Light throttle shudder between 25-50 mph. GM Customer Satisfaction Program 18302 extends coverage to 6yr/100k.

The 4T60E transmission in the Lumina develops shifting problems, particularly the second clutch reaction plates that were improperly stamped in some production runs. The transmission can lose 1st or 4th gear, develop harsh shifts, or strip planetary gears causing complete loss of drive. GM issued a campaign for certain 1995 models with defective clutch plates.

The 4T65-E automatic transmission used in the 2000-2013 Impala is one of the most failure-prone GM transmissions. Common failures include the 1-2 accumulator piston cracking (causing harsh 1-2 shift), pressure control solenoid failure (erratic shifts and slipping), and the forward clutch hub cracking (complete loss of forward gears). The 3.8L supercharged models are especially hard on the 4T65-E due to higher torque output. Many 4T65-E transmissions fail between 80,000-120,000 miles.

The 2016+ Malibu with the 1.5T engine uses a GM/Ford co-developed 9-speed automatic (9T50) that can exhibit shudder, harsh shifts, and delayed engagement. The 9-speed is sensitive to fluid condition and requires proper DEXRON HP fluid. GM has released multiple TCM calibration updates. The 2.0T Malibu uses a different 9-speed (9T65) with similar but less frequent issues.

The 2015-2020 Tahoe uses the GM 8L90 8-speed automatic with the same widespread torque converter shudder affecting Silverado and Escalade. Shudder occurs at light throttle between 25-50 mph. Root cause is torque converter clutch material contaminating the fluid. GM extended warranty to 6 years/100,000 miles under Customer Satisfaction Program 18302.

Express 2500 and 3500 vans built through roughly 2009 use the 4L80E. It is a genuinely strong unit, but the torque converter lockup clutch is its recognized failure point on high-mileage commercial vans. As the TCC lining wears, the transmission raises line pressure to compensate, so the first thing an owner notices is not slipping but hard, banging shifts - a symptom that gets misread as a valve body or solenoid problem. Shudder at lockup speeds, a bucking sensation around 45-55 mph and eventually a stall-on-stop follow. Related, heat and vibration kill the 2-3 shift solenoid, and GM bulletins for these vans document harsh shifts, a delayed 2-3 shift and slipping in third with solenoid replacement as the remedy. A separate quirk owners report on Express vans specifically is transmission fluid pushing out of the vent tube when the unit gets hot and the fluid expands, which then reads as a leak. Realistic service life is 120,000-180,000 miles; converters on 200,000-plus mile vans should be assumed suspect.