Discussion Starter · #1 ·
My auto transmission just started down shifting when cruising. Not all the time tho. I just recently changed intake and put a 4 barrel qjet carb on it and thought I didn't put vacuum lines on right but I tried different ports and even checked with vac gauge. I thought trans was slipping but its only showing about a pt low and has Lucas oil in it. Also it runs up in the rpms before it shifts from 2nd to 3rd unless I tromp on it. Thought maybe it was the vacuum modulator on the transmission or hooked up to wrong vacuum port. Drove the car over 150 miles without a problem so find it hard to believe the trans is actually slipping. Any other thoughts?