TRX400FA Angle Sensor Problem or EMC???

[JCollins]

Error codes indicated angle sensor problem on a 05 Rancher AT (TRX400FA). Trials and investigation indicated same. Replaced angle sensor, preloaded, preset, reset, and did all (I think) the service manual said to do. Seemed to work fine during initial test run but is rapidly digressing to previous state. If you slow to turn or are puttering around and try to throttle up or come upon the need for more throttle the machine does not seem to down shift but tries to continue as if in high gear. If you come to stop you can hear the Hondamatic hum and then you can proceed fine, it has down shifted. Problem only in Auto, works fine in ESP. Any help please!!!!! Driving me nuts. Haven't rechecked problem codes as yet. Also has new oil and filter. Thanks for any suggestions!!!!