65 Fairlane rearend problem

65 Fairlane with an 8" rearend, has a vibration from the rearend from 5 to 35 mph, then goes away, will also go away under hard acceleration, I know the drive shaft and u-joints are good-what else?
It runs quiet so I don't think it's bearings, but couls be and am usually wrong

 

Ring and pinion teeth with excessive wear will cause a vibration like you describe. One of my galaxies did it at the same speeds as yours. The teeth were worn to a fine point. I had a late model chevy truck in the shop recently that made the same sound and found the same problem.

 

hope not, will it last for awhile as long as I baby it?

 

How long was the car not uesed? Could it be a dose of ring gear rust above where the oil line is? Don't laugh, it does happen. If this question is true, you will have a noise that equals tire rotation speed, making an intermittent driveshaft speed noise as the pinion gear engages the ring gear. ID'd this problem in a motorhome over 10 years ago, had been parked for 7 years.
If so, why? A rearend is not filled to the top with oil. The airspace above the gear oil breathes with temp cycles as the vehicle is driven or parked. A vehicle that has been parked for x# years will also draw moisture with daily heat/cool cycles. Water in oil too? Iron and water?
Thinking tips.

 

Turned out to be incorrect pinon angle, thanks for the help anyway!

 

Tell us about your car Jim ??

 

65 Fairlane 500, original 289, automatic, drive it 80+ miles a day. No ac, power sterring or power brakes. gets 20+ mpg. Body is in pretty good shape with minor rust.
Plan is to save original motor and trans, upgrade to newer and stronger, new front suspension, ac, power brakes and paint and interioir. It will be kept as a daily driver, just more fun. Oh and a stereo, the factory am is no longer working.

 

Kewl.....I'm a bit partial to the 65 lanes. I call them " Lunchbox " styling