My dad has a 1991 Z28 L98/700R4. When we got the car, it didn't really shift. It only went in 2nd(maybe it was 1st, I couldn't really tell), and then slammed hard into 3rd as you neared 60mph or so. Wouldn't go into overdrive. A dealership worked on it, replaced the valve body, flushed the trans, and it was alot better, not perfect, but alot better. Me and my dad drove it on the highway for maybe 10 minutes and then it just started working right, and it was fine for the next few weeks. Started acting up again(not shifting, slamming into gear finally), and he stopped driving it. Then on a nice day here it started shifting right again. Few days ago started acting up again, and just yesterday he drove it to the store. He said as he left the store he stabbed the gas and then it started working right again. I took it for a test drive and it was shifting even better than ever, smoother than it ever has since we got it a few months ago. Barked 2nd, shifted smooth, everything was great.

What could be the problem? When these transmissions go out, can it be intermitten like this? It seems like the trans is good, but is finikey about shifting. It's never gotten us stranded, always gets you where you want to go, but it just doesnt want to shift right sometimes. I adjusted the TV cable, whenever it stops raining here I'm going to try and adjust it again. Anyone have any ideas? Thanks

 

It sounds like your tv valve is sticking. Its very common with the 700r4's after 120,000 or so miles. Transgo makes a kit to fix this problem.

Good luck,
John