Hi!
I have a 1988 IROC-Z with a 383 TPI and a 700r4 trans with a 3000 stall converter.
I bought a trans rebuild kit from Dana a little over a year ago. I believe the following link is it: ( https://www.700r4l60e.com/store/prod...&cat=52&page=1 ) I had a trans. shop rebuild it for me, and its been good til now. I've recently started to do more tuning to see what the car likes best. On Sunday I found a nice stretch of road in the country to test the car out. Everything seemed OK, but then after I got home, and had the car sit for a couple of hours while I was plugging in some data. I went out again and the car would not get out of first gear, unless I put it into neutral then back into drive at about 20mph. Which it then shifted into second etc. I also could not get it shift if I did it manually as well. It also would seem that once the car warmed up it would shift fine. I was told it could be the detent cable needs to be readjusted since I've playing with the idle so much, or the governor maybe sticking.

Tried it out this morning after resetting the detent cable. Car shifted fine at first, but then about a 1-2 miles down the road it started to not shift again, unless I put it into neutral then back in drive to make it shift. Again it won't shift at all in manual.