Hi all, I have a 2004R in my '67 Skylark behind a 340. The previous owner did the swap. The transmission shifts great through all gears. However, there seems to be a problem when cruising in 4th and downshifting. When you push the accelerator down and the transmission downshifts, it will downshift then immediately shift back into 4th, then downshift again and immediately shift back into 4th. It will continue to rapidly cycle between gears like this until you let off the accelerator. If you manually downshift the transmission with the shift lever, none of this occurs and it downshifts smoothly. Does anyone have any suggestions on what could be causing this odd behavior? Thank you!