Re: Tranny problem getting worse, buy a replacement tranny (if possible) get mine rebuilt, or... Most of us drive our cars too easy. They should be "driven" but not beat. If you add the seafoam be sure that what you add does not overfill the transmission. I also believe it is Jon [63viking] that has put Type F fluid in his car. He has added a supercharger to his car and then had to rebuild the tranny. From what I remember he has had no problems with using the "F" fluid. I did not HAVE to rebuild my transmission after I installed the S/C. I had the transmission "Hardened". All internal parts that could be hardened were. Then I installed type F fluid. The shifts are a little harder, but not bad. Also you can still adjust the shift with the vacuum control. I put the type F in because I wanted to: 1 Save the transmission, 2 get better shifts.