My stock 53 AD (216, 3sp) is acting up at about 35-40 mph. In this case I actually can't tell whether it's engine, trans, or further back. Get it up to 40 and it has a low rumble and some vibration. If I back off the accelerator a little, "coasting" at 40mph+, the rumble goes away. Thoughts?
Any simple checks to diagnose?
PM
