The first place I look for the cause of unusual shifting is the kick down cable which is attached to the spool on the throttle body. Sometimes the cable hangs up in the housing and you can buy some time by lubricating the cable. Other times replacement is called for. It should move freely and not bind up as you activate the throttle.

It is easiest to lube it after it has been removed from the spool and held up so gravity can run the lube down between the housing and the cable.

Randy

Check fluid condition and kick down cable adjustment first.

The kick down cable is the one that comes into the bottom of the throttle bobbin. When it is set properly there should be little to no slck in it and when you pull it out about 1/2-3/4" and let it snap back you should be able to audibly hear a "clack" noise from inside the trans. That is the wheel that it runs on smacking back against its stop. If it is too loose you will find yourself in top gear almost immediately and if it is adjusted too tight it will take too long to go through the gears and it will snap your neck when it shifts. You can see that it is held in place by two nuts, check the adjustment and if it needs adjusting then do so. Loosen the nuts and adjust it in or out to get the desired effect.

Mark