DRIVESHAFT VIBRATING ????

[ianlink]

Just picked up a 67' Datsun 520 pickup here in Grand Junction,CO. It was purchased here in 67' at Market Motors and came with the complete service history and manuals from the dealer, its in great shape and was restored a while back. Anyways, I am getting a rough vibration from the driveshaft at 30-40mph. Been trying to diagnose the problem, it is a one piece driveshaft, can anyone please give up their two cents........

[bilzbobaggins]

bad u joint?

[DaBlist]

If not u-joints try swapping your tires front to back. Sounds stupid but my tire guy has lots of stories of drive line problems that turned out to be wheels / tires.

[ggzilla]

Sounds like tires.

[metalmonkey47]

Tire balance probably.

 

I had a pulsing vibration that would start around 50mph, that was front end alignment. (Excessive toe-out.)

 

 

 

If it was U-joint, you would probably see it at lower speeds too.

[datsunaholic]

U-joints can cause vibration at harmonics too. Usually from being dry. Friend of mine assembled his new U-joints with no grease... they vibrated pretty bad. But usually vibrations like that are tires

[ianlink]

yeah its really strange, we put it up on jack stands to see underneath it, the driveshaft looked like it was shaking pretty bad @ 30mph.......

[Draker]

Balance the tires... or swap front to back. If still there pull the drive shaft and go have it balanced.

[ianlink]

the driveshaft has a little bit of play in it when you wrap your hand around it and turn it...is this normal, we tried it on my buddies fairlane and it was not moving at all....thanks for the help.

[datsunaholic]

They usually don't shake. If the U-joints are broken, not installed right, or worn out you'll be able to feel that, they shouldn't have noticeable movement when the driveshaft is installed. There WILL be some play in the entire driveshaft due to gear lash in the transmission and differential, THAT's always there. But there should be no play in the u-joints.

 

Other possibilities are a bent driveshaft, or it's no longer balanced.

[datzenmike]

U joints are the first likely. If the driveshaft is wobbling then you should be able to see the Broken/damaged/worn U joint causing this.

 

The 521 has a slip shaft? or splined rear driveshaft. When these are worn the driveshaft will wobble.

 

 

Balance the tires... or swap front to back. If still there pull the drive shaft and go have it balanced.

 

Well he said it was up on jack stands so I assume the stands are under the rear axle.

[datsunaholic]

It's a 520- they have a normal single-barrel driveshaft. No carrier bearing, and a slip yoke at the transmission like a car. The PL521 was the first to get the 2-piece driveshaft with the carrier bearing, and they used the center slip spline like a 4X4.

[69srl311]

Sloppy tailshaft bushing on mine causes a driveline vibration upon deceleration. If I press on the clutch before I let go of the throttle it will coast smoothly.

[ianlink]

yeah we had the jack stands under the rear axle so i don't think it could be a tire issue, It sounds like I will be pulling the driveshaft and replacing u-joints and getting that sucker balanced.....thanks for the help again.

[ggzilla]

Tires vibrate wether on stands or not on stands. Don't try the easy test, go on and do more complicated things.