I have a '02 Trailblazer w/ 206k miles, that has been having the issue of not going into overdrive. The 1-2 shift seems fine but the revs seem kind of high when it does make the shift as well as going into 3rd. Once in 3rd it will rev pretty high and will slip when it tries to shift and even stays what seems like to be out of gear. Only letting off the throttle and letting the rpm come back down will allow it to go back into gear. I have recently replace the trans filter and fluid as well as the 2-3rd tcc shift solenoid which did seem to help some of the shifting a bit. Im pretty mechanically inclined but have no clue about auto transmissions. At this point I have no idea what to check next, any help would be appreciated.