I have a 700r4 in an 86 Iroc-Z28 and was going to work today and noticed it wanted shift VERY late through the gears. It's the same at WOT but its fine then, but if i take off slowly, it eventually waits too long and i get nervous cuz the revs sound high only going 15 in 1st so i just give it some gas and get it to shift. My TV cable is hooked up and has no play, and my tach doesnt work but judging by sound it sounds like it wont get out of first until 3000 rpm, which gave me a little spook this morning on a wet road (lol). any ideas on if my trnsmission just might need a service or is just going out? thanks!!

 

Stuck throttle valve or broken governor?

 

You said your TV cable is hooked up good but is it adjusted properly?

 

I agree with with both diagnosis...first check the adjustment of the TV cable. A governer or throttle valve malfunction seems feesable too. does it shift ok going into third and fourth or is it just the 1-2 shift?

 

Mine was doing something similar on my TH-350. I added more trans fluid and it went back to normal. Try that first, you could always get lucky like me.