When I press accelerator down to the point where you feel a hesitation and if I go past that point all the way to floor it drops into passing gear and stays in that gear when I let off accelerator and the only way it will shift as it is suppose to is park the car till the motor gets cool.
If I do not go past the hesitation point it will down shift and works as it should. Any suggestions? Thank you

 

My guess as such

Vac modulator is in need of a replacement.

Trans fluid is grubby, and the slide valve behind that modulator is sticking in the valve body. Common and easily fixed.

 

Grant is probably right. Check the modulator.

Based on on your description of the throttle action another possibility is your lockdown switch or its slide activating mechanism on the throttle cable is sticking. Easily checked by disconnecting one of the switches connections.

 

I put a new modulator, 73,000 miles on car. How to fix the slide valve?

 

What is the lock down switch and where is the slide activating mechanism on the throttle cable ?

 

Bernard's pic. I'm up in the NC mountains with one cell bar. The switch is under the flat metal cover. It sticks into a void in the steel sleeve on the end of the cable. I'm not sure about the insides of the mechanism that slides. I've never had to work on mine. Have someone stepped on the throttle while you watch the slide mechanism. At the end of the stroke it slides a sleeve up and trips the switch. Probably need some lubrication.

 

Thank you, I will check that out tomorrow and post the results.

 

Just unplug the wires from the switch and see what happens. If that switch is engaged it will always want to stay in the kickdown gear.

 

I cleaned the slider and lubed,it was moving back and forth maybe 1/4" and coming back to the screw that is in the cable, also about 8" south of there is a set screw that moves a switch and I messed with it readjusting.
It still gets stuck in passing gear but now I'm able to get it to shift into 3rd by kicking the accelerator a few times which it would not do before.
There are 2 electrical plugs under the metal plate and an electrical plug at the southern location I mentioned, could these switches be bad or is there something else I need to do?

 

The switch under the metal plate could be faulty. Meter it and actuate it and make sure it's going open reliably. It can also be cleaned and lubricated. The spade connectors on it and the plug are both fine or it would not be able to cause the kickdown.

The cable slide is still the most likely villain here. It may require more invasive cleaning / refurbishment.

In the meanwhile, I'd disconnect a spade on the switch. I'd rather have no accelerator-triggered kickdown than randomly be stuck in 2nd.

The vacuum actuated kickdown modulator should still provide kickdown when you demand a big throttle and without reaching the slide activation portion of the stroke. I don't know the spec, but on mine, any significantly heavy foot will trigger it just when you'd expect it.

Im assuming yours is fine since it's newly replaced but if you're not getting any kickdown unless you're hitting the slide mechanism then you may have a vac leak.

 

It has kick down and runs perfect until I push all the way and activate the slide mechanism, that is how I have been driving it. A GM mechanic once told me to disconnect the lock in lock out switch, I assume that is the same switch you are referring to ?
I will try cleaning the switches as you suggest.
What is that other switch that is south of the slider?
If it still does not shift right after cleaning I will disconnect the switch and drive it that way till I replace the switches.
I will let you know what happens.
Thank you again for all the info it has been very helpful.

 

I disconnected the lock out switches and it shifts good, If I need passing gear between 65 and 80 I will manually drop it into 2nd, up to 65 it drops into 2nd as it should. Going to let it go at that.
Thank you for the info, I would not have figured it out.