I was a transmission engineer for 19 years. I never heard of letting it run for 20 minutes before trying to drive it. Why would it need that? What would it do? If it isn't going to work in the first 5 seconds it sure isn't going to work in 20 minutes.

I think that you have a mechanical failure inside the trans. As you saw the solenoids are not the problem. Nothing electrical is going to cause this.

 

Yep, I agree with Mark, Your dad didn't mess anything up! The problem was already there.
You changed a part, You probably need to rebuild the tranny.

 

Wow! Thanks for agreeing with me, even if it is 3 years later!

 

That was funny Mark! I agree with you too. Dad didn't mess up the tranny. It sounds like it needs a rebuild. I wouldn't throw any more money at it with any more solenoids.

 

Hopefully you weren't mad at him for 3 years lol.

 

And now you brought up a thread that was dormant for almost a year...smh.

 

And you think no one's had a tranny issue since then.KMA