Q: 2007 Acura mdx 125K miles. Won't upshift above third gear. Codes p1717, p0842, and po743. Do I need a new transmission?

Hello, thank you for writing in. In this situation facing a potential several thousand dollars repair, you will likely feel better with a second inspection. The codes you have are for several electrical systems on the transmission. These do not automatically mean you have a mechanical failure that warrants a swap. Without testing the sensors and evaluating the transmission by removing the fluid pan (which you might as well change the fluid and filter at that time), it can end up a costly guessing game. For a second opinion and inspection from us, contact our service department to schedule an appointment.

The pressure switch to the 2nd clutch circuit has an internal leak. I recommend replacing the 2nd clutch circuit switch (solenoid). The codes are also on for the torque converter not locking up and the transmission fluid pressure sensor has found a loss of pressure within the transmission. I recommend replacing the transmission fluid and filter (as long as the fluid is red in color and not black) If the fluid is black, then the transmission is burnt and needs replaced or rebuilt. If the fluid is red or dark red, then there is no problems with replacing the fluid and filter. Usually the filter tends to plug up and cause the fluid to not reach the pump making a loss of pressure. If the oil change and filter on the transmission and the solenoid replacement has no effect, then the transmission will need rebuilt or replaced. If you need further assistance with your transmission slipping in second gear, then seek out a professional, such as one from Your Mechanic, to help you.