Chrysler Repair: transmission fault codes for 1999 Dodge Avenger, solenoid switch, dodge avenger

Question
I noticed a downshift problem on my car when I came to a stop.  It felt very "clunky".  No problem with accelerating up to highway speed except that I noticed my RPM was 2500 instead of the usual 2000 for the same speed.  No loss of power, just more RPM to go the same speed.  I was planning on calling my mechanic the next day when the "service engine soon" light appeared on the way to work.  I obtained a scanner and the following codes were shown:  P031, P1775, and P0700.  I want to take my car for repairs, but are these codes something a regular mechanic can fix or should I find a transmission specialist ?  For safety reasons, I have not been driving the car since the light illuminated.  I don't want to cause any harm to the transmission.

Answer
Hi Kathleen,
The 1775 switch code says that the solenoid switch valve that is involved with locking-up the torque converter for fuel economy (as you noticed the rpm being 2500 instead of 2000 is exactly what would be the manifestation) is not locking up and also when it is locked up it may not unlock promptly when you slow down whick causes the harsh behavior. It could either be the switch valve in the valve body is sticky in its function (and that could be checked by removing the valve body from the transmission) or the lock-up solenoid on the torque converter could be malfunctioning (which would require removal of the transmission to repair that). You might do well to authorize the valve body check/clean and change out the trans fluid at the same time as a less expensive option to doing the trans removal which is very much more costly. See what a competent non-franchise transmission shop suggests and let me know what they are recommending.
The 0700 is just a proforma code to see there is a transmission code also stored in the memory. The 031 is not a 4-digit number, so let me know what it is actually. The 0131 code would say that the oxygen sensor on the exhaust manifold has a wire shorted to ground, which probably means the sensor is needing to be replaced. It is a simple replacement and the sensor is under $100.
You can safely drive the vehicle, but seeking a proper repair promptly is adviseable.
Roland
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Sorry for the delay in answering but I just found your question in the 'pool' to which the other expert had referred it.