P2714: How to Diagnose & Fix — Pressure Control Solenoid D Performance/Stuck Off

The ZF 8HP70 eight-speed automatic transmission used in the L494 Range Rover Sport develops valve body and mechatronic unit faults. Symptoms include harsh shifts, delayed engagement, and occasional limp mode. The solenoids in the valve body wear and cause improper fluid routing. The transmission adapts by increasing line pressure, which accelerates wear on the clutch packs.

The GM 6L50 6-speed automatic transmission in V6-equipped STS models is prone to overheating and developing harsh shift quality. The transmission fluid cooler is undersized for the vehicle weight, and the valve body solenoids degrade from heat cycling. Fluid darkens rapidly, and shift quality deteriorates with delayed or slipping 3-4 and 5-6 upshifts. The torque converter clutch also fails prematurely from heat damage.

The VT40 continuously variable transmission fitted behind the 1.5L turbo from the 2019 model year onward develops a sticking clutch regulator valve in the valve body. Pressure to the forward clutch falls off, the car shudders or bangs on the 1-2 engagement, delays going into drive after a cold start, and eventually sets P2714 (pressure control solenoid D stuck off). Forum teardowns report damage to the forward clutch piston and wear in the primary pulley bearing bore by the time the code appears, so the valve is only the first domino. This is a different transmission from the 6T40 and 9-speed step automatics used in other Malibus, and it fails differently: it slips and flares with no gear change rather than shifting harshly. Reports cluster after roughly five years in service.

Second-generation Tundras with the AB60E/AB60F 6-speed automatic commonly develop a torque-converter clutch (TCC) shudder felt as a vibration or 'rumble strip' sensation during light-to-moderate acceleration, typically between roughly 20-45 mph as the converter clutch tries to lock up. Toyota acknowledged the condition in TSB TC018-07 for 2007-2008 trucks. In that TSB, Toyota addressed the original torque converter design and released a redesigned converter. A worn torque-converter clutch and wear in the valve body TCC control valves also contribute, often aggravated by using fluid other than Toyota WS or by long fluid-change intervals. Left unaddressed, the slipping clutch contaminates the fluid and can damage the rest of the transmission. Common stored codes are P0741 (TCC stuck off) and P2757 (TCC pressure control).

When the Express moved to the 6L80 and 6L90 six-speed for the 2010 and later vans, it inherited that family's torque converter clutch problem. The TCC lining delaminates, and the shed material scores the fluid pump - so what starts as a light shudder felt at steady cruise, often described as a chuggle or 'fish bite' between roughly 35 and 60 mph, progresses into a pump and converter failure that takes the whole transmission with it. GM's own path on the complaint is graduated: TCM reprogramming for the chuggle concern, then a fluid exchange to the specified low-viscosity synthetic ATF, and finally converter replacement when the clutch is too far gone. That progression is exactly why the shudder must not be ignored - the flush only works if the wear is caught early. Documented as a 2010 and newer issue only; do not attribute it to the 4L60E/4L80E vans.