Was driving my 99 montero today and noticed wasn't shifting like it should. It seems to be fine until i get to about 40-45mph then the RPM's just keep going higher and wont shift. And some points while just cruising (not accelerating and/or decellerating) the RPM's will flucuate a litle bit on their own. Checked the fluids and all are fine. When shifting manually it works fine until you get up to that speed. Think it might be the O/D because if I click the button on the shift the RPM's stay the same. Any ideas on what it might be would be appreciated.