B737-800
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 509
Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Less Severe
General None Reported / Taken
Aircraft
During cruise flight on Autopilot 'A;' I applied forward control column pressure; expecting control wheel pitch mode to engage. What I got was manual pitch with autopilot disengagement and an abruptly sharp disconnect on the control column. After reengagement I tried Autopilot 'B' and received the exact same response. Neither autopilot would default to control wheel pitch or steering mode. I also tried turning the control column and got the same abrupt autopilot disconnect. There was no amber indication of CWS or CWP on the FMA (Flight Mode Annunciator). I engaged the Autopilot again and selected CWS by the switch. The result was exactly what it was supposed to be. It released the control column smoothly and defaulted on the FMA as CWS-S/P. This is now the fifth aircraft that I have written up with the exact same conditions. I have found that all B737-700s work correctly. I am noticing that all -800s and MAXs operate the same. It seems to either be; I do not understand the system or there is a problem with CWS/P Autopilot system on these two aircraft. I have not found one B737-800 or MAX that operates the way it is described in the [Flight Manual]. The feeling on the control column is as though the pilot is fighting against the autopilot. A Pilot will have no indication that anything is wrong until they try to use it. Autopilot operates normally. Somebody needs to either change the books; or we need Maintenance to look at all -800's [and] MAX's and fix the issue. Something is not letting the flight controls release. I hope a cable does not break in flight.
Reporter stated Maintenance found the Flight Manual was incorrect; and the -800 and MAX aircraft do not revert to CWS when pressure is applied to yoke with autopilot on; they respond with autopilot disconnect; and this was not properly spelled out in the manual.  Manual is being corrected at this time.
Captain reported the B737-800 and B737 MAX autopilots do not function as expected in certain modes of flight.