vibration

fumey · #1 03-16-2005, 10:21 PM

My truck has developed an annoying vibration/hum this past week that seemed to suddenly just appear. It starts when cruising around 55 mph, gets louder till about 70 mph, then seems to wind itself away the faster I drive. At first I thought it was an exhaust leak, but I can't locate any thing with the engine at idle, sitting in the driveway. Then I thought it might be a tire, but psi's are all ok and and all the weights look like there still there.Besdides ,the vibration isn't in the steering wheel, it's in the accelerator pedal and the floor. Also, it goes away when I take my foot off the gas and returns when I put it back on. RPM's seem to have nothing to do with it . The tranny's been flushed three times and the fluids a healthy cherry red, and I've also changed the oil in the diff. frequently. Gas mileage and preformance are normal. So I'm asking for any suggestions. Thanks guys.

kokopelli · #2 03-17-2005, 04:17 AM

fumey , ........my first though is a universal joint , have you greased the rear u-joint and splines ?

fumey · #3 03-17-2005, 05:59 AM

Yup,at every oil change.

#4 03-21-2005, 03:18 AM

Depending on the milage of the truck...the drive shaft center support bearing might be wearing out. That would surly cause a vibration. Its also un-greasable. You might have a weight that came off the drive shaft.

I recently had a vibration start, I originally thought it was in the drive trane because it was a pulsating vibration not normally associated with tires out of balance. The dealer said my tires were cupped a little and that was the cause of the vibration.