Transmission issue

I just changed the fluid on my tranny in my 2.4 Taco (1996). New filter as well. Now it won't shift into overdrive when I get over 45mpg or so. The rpm's are near 3000 when i am going 60mph. It shifts through the other gears just fine.

What gives? The overdrive switch is NOT turned off, BTW.

 

The fluid level is correct, yes? And the correct type of fluid was used? Just getting the obvious stuff out of the way.

 

I used the O'reilly brand for the Dextron II/III and the fluid is at the top notch on the stick when hot and at the lowest when cool.

 

How many miles on the truck? How many miles on the transmission since the last times you changed the fluid? Sometimes changing transmission fluid can do more harm than good.

 

About 153k on the truck, but the engine was replaced about 2yrs ago. I had the transmission rebuilt around the same time, too. That was the last time it had new fluid.