The run down. 96 2500 12v. 80+HP injectors. #0 fuel plate. 35psi on stock hx35. I'm unable to get the trans to shift into overdrive until I completely let of the throttle. I'll be running 55 mph @ 2100rpm with no OD shift. I've taken it all the way up to 63mph @ 2500 and nothing happens. Once I let off the throttle and and give it 4-5 seconds the rpm will drop to 1450 and OD kicks in. At this point I'm doing 50ish. Accelerate to about 55 and lock up engages without a problem.

No TC slip. No dropping out of lock up. New tps ranged to 1.1V at idle. Replaced fluid and filter. Checked throttle cable and throttle arm for wear and there both good. Adjusted TV cable with noticeable shift change but no change in OD shift. Also swapped trans speed sensor.

Any ideas would be greatly appreciated.

 

Welcome to DTR.
I am no auto transmission expert, so I will let others on the forum chime in on the problem.
I do know that '96 12V came with the 47 RE, not the 47 RH which was the auto transmission use in '94 and '95.

 

Thanks for the welcome. I've always read through these forums and they are extremely helpful. Unfortunately I haven't found a forum with my symptoms. Hopefully these guys can shed some much needed light on the topic.

 

Your '96 did come with a 47RE, which means it's electronically controlled unlike the 47RH which is hydraulically controlled. Several transmission techs are on this site. Hopefully one will see this and chime in.