Undersized Spacer Plate Leads to Shifting Conditions

Some 2018 Enclave, LaCrosse and Terrain models — from start of production to September 28, 2017 — may have several automatic transmission shifting conditions. These conditions apply to Enclave models equipped with the 9T65 automatic transmission (RPO M3W), LaCrosse models equipped with the 9T60 automatic transmission (RPO M3G), and Terrain models equipped with the 9T45 automatic transmission (RPO M3U) or 9T50 automatic transmission (RPO M3H).

During warm-up (transmission fluid below 32°F (0°C), a sharp deceleration may occur during the 1-2 upshift, as if the brakes were applied momentarily. The deceleration also may occur during a Manual 1 to Manual 2 upshift. During warm operation, a momentary neutral during the 2-4 upshift may occur, leaving the transmission stuck in 2nd gear. The Malfunction Indicator Lamp also may be illuminated.

In addition, DTC P2820 (Transmission Control Solenoid Valve 9 Stuck Off) may set in cold ambient temperatures after three consecutive failures during the same key cycle and the transmission may be limited to 1st gear operation.

Inspect the valve body spacer plate. (Fig. 10, #1) The shifting conditions may be caused by an undersized spacer plate orifice (Fig. 10, #2), located between the valve body and the transmission case. As a result, the clutch selector valve moves slowly to release the selectable one-way clutch, which causes a momentary transmission tie-up during the 1-2 upshift.

Fig. 10

If the spacer plate orifice is 0.5 mm (Fig. 11, A), replace the spacer plate. If the spacer plate orifice is 2.0 mm (Fig. 11, B), continue with the diagnostics outlined in the appropriate Service Information.

Fig. 11


– Thanks to Mark Kevnick

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