Transmission problem...???

Hi!

I need your help because I have no more idea what to do.
So. it is a 1990 Jeep Cherokee, 4L engine, 6cyl in line, 220.000 Km on it.
A few days ago I left my car in good conditions , I washed my engine and under the car and next day...problems with shifting.
The first gear changing is between 60-70Km/Hr., time enough to the coolant to ridge 100 celsius(after I drive ~5-10 km at 50K/h in town)
With other words, the transmission is working-shifting, but the first gear changing is to late.
I did the test by pulling the fuse.With or without fuse it's working the same.
I start with 1-2 than I swith to 3, than D, but the RPM remain the same.When I downshift to 1-2, I can feel the engine brake, the car slow down.
I cheked all conectors, they apears to be in good condition.I put in new filter kit and new fluid.

It is anything else to do? Any idea?

THX a lot.

Wow, 220K K, which is what 130K miles.

Make sure the TPS (throttle positon sensor) and connection did not get wet.
Check the kickdown.