Vibration in drive train
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Vibration in drive train
I have a 1993 ext. cab, short bed, chev. pu with 350 v8 auto-trans. It vibrates when the motor is not in a strain. I can be going 55 in overdrive and it will vibrate, but I can shift to drive2 and it will stop. It will also stop when I either give it gas or let off the gas. The faster I go the less it will vibrate. I bought it used last year and it did it some then but it got worse. I replaced all three U-Joints and the support bearing last month but it still does it. What could be the problem?
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You have a bad spark plug or wire. When was the last tune up? When the truck shifts into overdrive, it creates more load on the engine. This will amplify a weak or leaky spark and create the condition you described. While in overdrive at a steady speed, if you just tap the brake pedal, this will disengage the overdrive. At the same time, I bet your truck no longer does what you say it does, until it shifts back into overdrive.