P0700 on Buick

Separate from the well-known low-speed shudder, the VT40 continuously variable transmission suffers hard failures of the line-pressure control solenoid circuit. When the solenoid sticks off, the belt-and-pulley set loses clamping pressure, the transmission cannot transmit torque, and the vehicle abruptly stops accelerating - owners describe engine RPM climbing with no forward motion, or being unable to exceed 20 mph with the pedal floored, sometimes on a highway. Failures are reported between roughly 40,000 and 83,000 miles, and multiple NHTSA complaints describe a second failure after an earlier transmission replacement. Some units have been found with essentially no fluid in the sealed case at teardown.

The 2020+ Encore GX uses either the VT40 CVT (FWD 1.2L) or the GM 9T50 9-speed (AWD 1.3L). Both have reported issues: CVT hesitates from a stop, jerks on tip-in, and growls. 9-speed has been the subject of multiple TSBs covering harsh shifts, flares, and torque converter shudder.

The nine-speed automatic in later Envisions produces a violent intermittent clunk when engaging or shifting in Drive - described by one owner as 'so violent, it shakes the entire car' - with a tendency to slip on the 1-2 and 2-3 shifts, appearing around 14,000-15,000 miles. On Gen2 cars the same family of complaints escalates to a 'Service Transmission Soon' message with a total loss of acceleration that feels like the car dropped into neutral. One documented repair required replacing BOTH valve bodies, where the dealer found a nicked O-ring seal during disassembly. GM TSB 21-NA-169 provides diagnostic procedures for 9T45/9T50/9T60 fault codes, and TSB 23-NA-153 documents which shift delays are considered normal.