My 2007 Soltice Base has 31,000 miles and has developed a hard down shift issue. I have ask a number of “experts” in the field and have received numerous answers including everything from changing the MAFS and O2 sensor to changing out the entire transmission along with doing a complete flush and changing all the servos. One “expert” inisisted that the clutch on the torque converter was not releasing and said he didn’t believe me when I said the engine didn’t stutter and stall when I came to a complete stop. The fact is that it just shifts hard both going up in gears and coming down. When going from second to first it will actually chirp the back tires.
Is the Check Engine light on?
Tester
Has anyone checked the level of the transmission fluid?
Absent a pertinent diagnostic code, I don’t see this related to the MAF or O2 sensor. If it is related to a sensor, more likely the vehicle speed sensor. Suggest to start with a proper transmission service. Usually that means to drop and clean the pan, replace the filter, and fill up with fresh fluid. Make sure they sieve the old fluid and the bottom of the pan for metal debris, which can be helpful toward a diagnosis. If that doesn’t do the trick you’ll have to schedule an appointment with a transmission specialist. They’ll have the testing equipment to measure the port pressures, verify the solenoids and sensors are working, etc. From that and a test drive they’ll tell you what’s wrong and what’s needed to fix it. I’d guess you have an obstruction in the valve body or a failing or stuck valve.