93 240 transmission not shifting when cold

Ok. I have to admit. I did it. I did transmission service on my 200K tranny. Thought it would make it smoother.

Drained, changed filter/gasket and filled, then flushed old fluid via cooler.
Filled with Valvoline MaxLife Full Synthetic Multi-Vehicle ATF.

Now the tranny does not shift from 1st when cold. Warmed up and rides nice.
Level is good.

I am thinking the valve is sticking. I checked the kickdown cable and it is free and clear of issues.

What gives?

Govener sticking.pull tail shaft housing.

Give it some time to accept the changes. Yes it definitely can be detrimental to get in there and change fluid/service.

I’ve serviced two of my 240s before and this happend to both of them immediately after service.
When cold it won’t shift out of first but after warmed up it does fine. After afew weeks everything went back to normal. Both tranny’s shift fine now cold or not.

Give it some time and see what happens.

Update.

Added Lucas Tranny fix. No improvement. Still slight vibration on start too in 1st gear. Seems like 1st gear is slipping. Sometimes starts in 2nd gear if I do not give it enough time at the stop sign. FYI. I have new mounts all around, so there should be no such vibrations coming through.

Flushed fluid again with ScanTech Dextron III even though I noticed new black sludge on the magnets. Just for giggles since I have money to burn. lol. Flushed fluid is not "new" clear, but has a hazy cloudy gritty feeling.

Stuck in 1st gear for good now. Assume that the clutch disk is definitely gone and is swimming in the 2x flushed fluid. BTW. Kickdown cable is in very nice condition and moves freely, so it is not that issue.

Word to the wise, never flush fluid without knowing tranny maintenance history or checking out condition of existing fluid. I neglected to heed that warning this time while thinking it would be a different outcome.

Looking for another tranny.

Been there, done that. I had to replace a transmission this year as well. The transmission I have now operates very smoothly but leaks a little from the tail shaft bushing. When you find a replacement transmission I recommend you replace the input shaft seal, tail shaft bushing/seal and sealing rings/washers on oil cooler line fittings to avoid having a leaky trans.