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vibration

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#1 ·
Hi guys. Finally straightened out my cooling situation, now I have another question.

I am experiencing a heavy vibration from underneath the car at highway speeds. It only happens at about 60mph. The strange thing is that it only lasts 2 seconds then stops for 2 seconds, but it's very rythmic, not erratic. Kinda like-
rrrrrrrrrr -nothing- rrrrrrrrrr -nothing- rrrrrrrrrr -nothing- rrrrrrrrrr -nothing- and so on.

Only at about 50-65mph. That would completely rule out the engine and probably the wheels. I'm thinking either transmission, driveshaft, rearend or U-joint. Doesnt seem to come from any one side or wheel, pretty much the whole underneath. Steering and driveability aren't affected any, just loud and shakes a bit.
I only have a 2 speed auto, which would make for some crummy highway driving, but this just doesn't seem normal.
What do you think?
 
#2 ·
Check the u-joints. I always take the drive shaft out to check them. They may seem OK when it's all together but sometimes when you take the shaft out the u-joint are stiff or have tight spots.

Raise the car and spin the shaft to see if it's straight.

Check the pinion bearing and the bushing in the tail shaft housing for excessive play.

Also does it vibrate in neutral with just the engine running?
 
#5 ·
If you don't fine a U-joint either loose, and/or binding, and the driveshaft is straight, then I would check pinion angle. (first things first tho......check for any play/looseness/worn out parts in the rear suspension first). Wrong pinion angle can cause all sorts of noises/vibrations, etc.
Good luck.
 
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