Tranny wont shift 2-3 at WOT???

[AMMO_HOOAH]

Ok I need some help from you tranny guys. I've got a '96 4R70W today I was driving home and went to accelerate up a hill at WOT. The truck redlined in 2nd, and wouldn't shift into 3rd until I let off of the throttle just to make sure it wasn't the truck bogging on the hill I did it again on a flat road from a stop. I floored it and it ran up shifted 1-2 fine, but again wouldn't 2-3 shift until I let off the gas. When I floored it again it downshifted, and just stayed in 2nd. Any help is much appreciated. BTW I just recently put a temp sensor in a t-block at the top hole for the tranny lines that run through the radiator I'm going to take the t-block out tomorrow and see if the problem goes away.

 

[AMMO_HOOAH]

Bump

 

[IZwack]

Yeah that T-block could be restricting ATF flow. Also, a transmission thats low in fluid will red-line the engine w/o shifting unless you let off the gas pedal.

 

[AMMO_HOOAH]

Thanks for the into. Here's an update though. I took the t-block off today, and it made no differance. I checked the tranny fluid also, and its almost over full (very top edge of the "hot zone"). I also noticed something today when I tried it again. Right where it should shift it "feels" like it's about to... then doesn't. I read that the 2-3 shift is two bands releasing and grabbing at the same time. Well if I think I feel what I feel (stay with me here) it almost feels like the one band releases, but the second one doesn't take over where it should. Thanks again for the help guys.

 

[AMMO_HOOAH]

Any more ideas?

 

[MountaineerGreen]

Did you correct your revs per mile for your 35's? A false PCM input from a bad speed reading could make your shifts be off.

 

[AMMO_HOOAH]

This happened pre 35s.