C4 freewheels intermittently on startup, won't go into any gear, then will

I think this phenomenon is called "morning sickness."
https://www.fordmuscleforums.com/threads/c4-trans-takes-15-min-to-get-into-drive.503172/

 

The first time it happened, I was 150 miles into a 300+ mile leg of the drive and only stopped for < 10 minutes at a gas station so it wouldn't have had much of an opportunity to cool down on a 100 degree day. I continued to drive the car for the season and it's parked for quite a while now. It'll be fun to tear it down eventually and figure out what happened.

 

Still haven't dealt with this, but another 1,000 miles of driving and it finally happened again last night. This time I tested my theory. When moving from park, it will not engage until I go all the way down to "1", then I can come back up to "D". I'm betting something is indeed sticky in the valve body.

 

Agreed, 99% morning sickness is related to high mileage/old age trans.

 

This transmission was rebuilt in 2016 by a reputable shop, but eventually I'll get in there and take a look.

 

Haha, man this thing. Happened again today. I'll probably deal with it in the spring. This time it didn't matter if I went up or down the gear selector, until I got the car off high idle and lowered the rpm, then she went right in.

 

Potentially related is that I have a "wah-wah-wah" cycling vibration on deceleration, off the throttle, that has appeared recently as well. Could be trans or torque converter. U joints checked out fine, pinion angle hasn't changed.