Thanks for the suggestions. The engine is stock, vibrations just became noticeable last week. I have had the car over a year with no problems. Both u-joints are solid and the pcv valve seems fine. Still need to check the torque converter bolts and ignition.
67 289 engine vibration
On the freeway most noticeably above 60 mph, when on even flat road if I let off the gas, no problem, but when I give just enough to maintain speed I get a heavy vibration/shaking feel from the engine. Not violent like something is breaking, just too heavy to feel right. Doesn't do it when accelerating or when I let off the gas. I haven't started to try to diagnose yet... maybe vacuum advance? or ignition/timing?
Any thoughts or help appreciated!
Any thoughts or help appreciated!
1 - 8 of 17 Posts
A little better inspection...rear u joint is toast. Not sure if that's the problem, but I will start there.
Rear U Joint
Got the driveshaft off and the U-joint out. One of the 4 bearings was cracked and a piece fell off when it came out. no bearings inside, just dust and the inner part was obviously worn to a taper. The grease port to that bearing was clogged with what I presume was the remains of the needle bearings.
Got the driveshaft off and the U-joint out. One of the 4 bearings was cracked and a piece fell off when it came out. no bearings inside, just dust and the inner part was obviously worn to a taper. The grease port to that bearing was clogged with what I presume was the remains of the needle bearings.
Noticed the vibration still there after a week or so. Driving home from work yesterday it became terrible. Looked this AM and the rear U-joint is hosed on one of the 4 bearings - will need replaced again. Differential causing it to eat u-joints? Appreciate any suggestions.
Thanks for the suggestions, didn't know about the "relaxing" part. I figured if the differential was causing it it would be the pinion bearing. My concern about the pinion is because the old U-joint was fine for a year and a half that I had the car until it started to degrade and vibrate. The one I replaced has only lasted a few months.
Maybe a dumb question, but how much slop is acceptable between the pinion and the ring gear teeth. I haven't pulled the differential, but when the driveshaft was disconnected, I could rotate it a little between the teeth. 1/4" OK but 1/2" too much??? Foreign territory here and just wondering if it needs rebuilt or replaced. 8" stock rear end, 2.79 ratio. My 2004 F-150 has virtually none, but it is a lot newer.
As far as I know it is the original differential. Flange rotation is what I was referring to. Still have some vibration. Don't understand how the driveshaft can just get unbalanced if that is the problem. I'll keep at it. Thanks for the help.
1 - 8 of 17 Posts
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