Installed transgo shift improver kit last summer all was good until september when it started not shifting into 2nd until higher rpm's under light accel then into 3rd almost immediatly. Pulled valve body down last night. The 1-2 shift modulator sleeve was stuck inward. freed it now appears to move ok. Can that cause a prolonged shift into 2nd?
Thanks for any help in this area,Joe

Possibly.
You might also check the governor to see if it's free also.