Car shifting up and down while driving on a constant road

[denton]

my car started shifting up and down while driving on a constant road.i have taken it to a transmission shop and they have found the following fault codes when test with http://www.xcardiag.com/wholesale/ads-1s-pc-based-universal-obd2-fault-code-diagnostic-scanner-9.html:1642 anomalous engine speed signal,100 gear monitoring
Need i remove the tranny and strip?