Questions and Answers
Mustang Vibration
Q. Hello, I own a 1967 Mustang with a 289 engine, 2 barrel carburetor and a C-4 automatic transmission. It has power steering and everything is stock. Ever since I Purchased the vehicle it has had a bad vibration. While running the vehicle in park, simply by raising the rpm the vibration occurs and the steering wheel shakes.
You can also feel it through the seats and floorboards. I overhauled the engine shortly after purchasing the car and replaced the crank, cam, all the lifters and push rods, all the valves and springs, replaced the vibration damper and the flywheel. It still had the same vibration, so I replaced the torque converter. Still had the same vibration.
I removed the engine and took all the rotating items to a machine shop that specialized in balancing engines, and had the engine balanced. I assembled the engine and have the same vibration. Before I removed the engine to be balanced, I ran the engine without the transmission to see what it felt like. It reacted differently, but it did vibrate. When I put the engine back in, I again ran the engine without the transmission, and it felt pretty smooth, but after putting everything back together, it still pretty much has the same vibration.
Is it possible for something in the transmission to cause this vibration? I have had two torque converters in it, with no improvement, and also talked to several transmission people, but they didn't feel the transmission would do this.
Any ideas?
JimA. A great detective once said, "When you eliminate the obvious whatever is left, no matter how improbable, has to be the answer."
You've done just about everything to eliminate the engine as the cause of the problem. You didn't mention if you had the flywheel balanced, but you've been to through about the rest of the engine, I'll assume you did have it balanced as well. I'll also assume the engine and transmission mounts are all in good shape and not broken anywhere.
So, the answer would seem to be in the transmission. You can try swapping the transmission with another one and see if the problem disappears or you can have the one in the car now rebuilt and see if that resolves it. You should keep in mind that rebuilding may not cure the problem unless everything in the case is replaced.
This is a tough one to advise you on since there is no way to really pinpoint the problem but I really do feel the transmission is the problem.
