Taken from chevytalk.com
700R4 Throttle Valve (TV) Cable AdjustmentThe Throttle Valve Cable is attached to the throttle linkage. When the throttle is depressed, the cable is "pulled" progressively with throttle position. In addition to providing forced downshifts (kickdown), and progressively later (higher speed) upshifts at higher throttle settings, the throttle valve also adjusts main line pressure in the transmission. Operating a transmission with the TV cable out of adjustment, can, not only produce early, or late upshifts, but incorrect line pressure, as well. What this means, in simple terms, is that TV pressure that is too low, will produce main line pressure that is also too low, and will eventually "burn" the transmission clutches.
To adjust, on the throttle linkage you will have three things attached if you have cruise, two if not. One of them is of course for the gas, the one that is for the cruise control has a long slot in it (if you have cruise control), and the other is the TV cable (which is actually a cable), this is the one you need to adjust. Adjust the cable so that it will be pulled all the way, when the throttle is simultaneously opened all of the way (with the engine turned off, of course). The way to do this is, bolted to the manifold is a bracket which this cable runs through. With close inspection you will see it has a sort of D shaped button you can depress and slide the sleeve (cable housing) back and forth. The sleeve is what you want to adjust, by depressing the button. Press the D button and slide the sleeve toward the firewall as far as it will go and let go of the button. Now open the throttle to the wide open position and release. You should be able to hear the sleeve click (rachet) as it slides through the cable housing. Make sure that the cable returns (with no binding) when the throttle is released. This preliminary adjustment will frequently be too "high", and the throttle pressure will have to be reduced, to attain proper shift points. I prefer to start with an adjustment that is "too high", and then work down, rather than "too low" and work up.
To raise throttle pressure (and raise shift points, and make "kickdown" more responsive) move the cable housing towards the firewall (away from the throttle linkage), as you simultaneously depress the button on the cable housing, move the cable housing away from the carburetor or (throttle body) to increase throttle pressure. Move the cable housing adjustment a small amount at a time (1 click or 1/16" or so), a small adjustment can often make a world of difference. Naturally, to lower the pressure (and lower shift points, and make "kickdown" less sensitive), move the cable housing towards the front of the truck.
1987 Chevy S-10 Blazer Supercharged 3.4 V-6 TBI