I have a 1952 car with three speed overdrive that about 60 mph has a pulsating sound comming from the overdrive. There is no vibration in the drivetrain. If the overdrive is not engaged, the car can be run up to 80 mph with no pulsation sound. I have had the overdrive apart two times and have replaced the planetary gear assembly with one that was supposed to have been rebuilt in addition to replacing the bearings. One person thought my problem was caused by the OD case having excessive wear. Has anyone had this problem and if so, know how to fix it? Thanks