Questions and Answers

Ford F-350 Has A Bad Vibration Q. I have a 1994 Ford F-350, 7.3 Turbo Diesel. Manual transmission, 222,000 miles, ABS brakes, A/C and cruise control. Over the last few months, I've been getting a bad quick bumping type of vibration. I've eliminated the drive shaft(s). This happens when I over rev even a little, even starting out sometimes.

When the engine is cold, I don't seem to have this problem, but after it warms up. Here's a description: I start out from a stop sign in second gear, usually no problems, but if I go over 1,800 to 2,000 RPM's (even if not shifting) I'll get a really bad vibration (but not all the time). I've tried to adjust my accelerator and clutch practices to make sure I don't rev the motor any during shifting.

This doesn't just happen in lower gears, its for every gear. I've even had it happen while pulling a little two horse trailer at a steady speed, going up a hill. So far I've been able to calm it down or make it go away, by putting the transmission in neutral and letting out the clutch for a while while moving. I've even pulled over to the side of the road, put it in neutral and let it idle for a moment, then accelerate a little and still feel it.

Thanks,
Steve
San Antonio, Texas

A. Vibrations are really tough for me in this venue. First thing I would do is pull the drive shaft(s) out and have them balanced. If they are balanced and you still have the vibration, it could be a loose flywheel bolt(s) or an out of balance pressure plate.