The purpose of the throttle valve (TV) cable is to control the TV system, working in a similiar way to the vacuum modulator and detent cable of the TH350 transmission. Depending on how it is adjusted will affect the shift points of the 700R4 transmission, making it either softer or harder shifts. It is important to note that if not adjusted correctly, the transmission may not shift at all.
First step is to take your car out for a test drive and make note of the of the shift points (in terms of MPH) while applying with medium throttle. The optimal shifting should occur as follows (give or take a couple mphs): 1st to 2nd -- 20 mph 2nd to 3rd -- 30 mph If your car is shifting at something different than above then move on to the next step to learn how to adjust the cable.
Before making any adjustments, it is a good idea to mark the position of the cable housing in the sleeve, a scribe works best. This is a precaution in case you can't get the adjustment right, at least you can return to the original position.
Now in order to adjust the cable for hard shifts and at later speeds, the housing needs to be shortened. See the diagram for the location of the components. To do this, press in on the detent button and slide the cable housing to a shorter length. Remember that this procedure, although easy, does require a lot of trial and error. Shorten the cable a little at a time and take the car out for a run again, testing at medium throttle and making note of the shift points. To make the shift point softer and at lower speeds, simply lenghten the position of the cable housing.
The final step is to ensure that the cable housing length is not to short. This part requires the help of a friend. Have him/her sit in the car and with the engine off, press down on the accelerator pedal to WOT. At the same time that your partner is doing this, you should have your head under the hood, paying particular attention to the TV cable. If the cable is adjusted to short, a clicking sound will be heard, because the cable is being forced to lengthen.
Below is a diagram that shows where the different location of components are that I talked about in the article.
