I don't know if I'm too late yet but the 904's behind the six's and eight's had problems with sticking kick down (TV) linkage. They would corrode where the TV shaft goes through the shift shaft and finally start to stick. Eventually it will become hard to press the gas pedal too. WD40 all of your linkage and around the TV linkage at the trans and work the heck out of it. Even if you have a cable it can be caused by a sticking TV shaft.
