02 QX4 transmission won't shift into OD

[honschoppt1]

So I'm wondering what's causing these problems with my transmission. Recently it seems that it does not want to shift into OD. Going 70 mph I am somewhere around 2600-2800 RPM and that seems higher than it used to be, almost as if the car won't shift into OD. Anyone have any prior experience with this problem? Only thing I've heard that can cause this is the oil temperature sensor going bad causing the car to think that it's never warmed up and thus preventing the transmission from shifting into OD. Any help is appreciated!