GM: 2007-09 Cadillac Escalade, GMC Sierra, Yukon, 2008-09 Chevrolet Silverado, Suburban, 2009 Avalanche, Tahoe
SUBJECT: Harsh shifting, flare or delay in shifting (2-3) might be caused by a leaking clutch fluid seal ring in the transmission. Another symptom is delayed or harsh engagement in shifting from Park to Drive or Reverse. The fix is to replace the clutch fluid seal rings in the transmission oil pump. The transmission must be removed and disassembled. This has part numbers, photos and instructions for installation of the fluid seal rings, but not for transmission R&R.
GM: Various 2006-07 Buick and Chevy; 2006-10 Cadillac and GMC; and 2006-08 Pontiac and Saab models
SUBJECT: On vehicles with a plug-in auxiliary engine coolant heater, MIL illumination and code P0116 and/or P1400 might be caused by ECT and IAT disagreement. Upon start-up, the PCM determines how long the ignition switch has been OFF. If the time requirement was met and the auxiliary heater was used to keep the coolant warm, one or both sensors will be interpreted as out of range. The fix is to relocate the ECT sensor and the auxiliary heater to different coolant passages.
Source: ALLDATA
