Chrysler Repair: Fault code 56 on 90 ETAX, 1990 chrysler lebaron, chrysler lebaron

Question
Hi Roland, I have a 1990 Chrysler Lebaron convertible, 6 cylinder - it was in limp-in mode ( would not move beyond 2nd gear). I took it to a transmission guy who read the code ( though his reader would not go earlier than 1992). It displayed fault code 56 and read turbine sensor error. The input would read 0 until it shifted into 2nd gear and there was no output reading. The input and output turbine sensors were replaced ( $310) and it worked fine for a short period ( 1 hour). It is now back to the exact same problem- will not shift beyond second gear and there is a distinct knocking at about 20 mph.
Thoughts?

Answer
Hi Rob,
Disconnect/reconnect the battery. Then drive it back to the shop and have trans guy read the codes again. If still showing a 56 then check the wires from pin 13 and 52 of the trans controller to the input turbine sensor for continuity/flaky connection. Let me know if anyother codes. If none other than 56 and wires are good, you could try another input sensor, and if that doesn't repair it then it appears to be an internal trans problem.
Roland