With the kickdown cable disconnected and fully retracted you will find that the transmission will shift much sooner than normal. If the cable is binding causing unusual shifts I always disconnect the cable and try to push it back into the sheath. With it in this position you can start off in L and manually shift to 2 and then D. If the overdrive is enabled (arrow off)it will shift quickly to overdrive. This manual shifting should give you a good indication of the condition of the transmission itself. My guess is that if the kickdown cable is not in the best of condition it is responsible for the bad behavior.

Replacing the cable involves removing the pan and working in a rather tight area. It helps to move the exhaust system but that is a major task in itself many times. It is not that hard to remove the old cable but getting the end of the new one in place without the spring loaded mechanism going to its home position is sometimes a test of will and a lot of luck. Good luck.

Randy