180* Drive Shaft Rotation - I'm A Believer

[Alan Reagan]

I've had a vibration in the truck at 70+ for some time now. I had the tires balanced twice (threw a weight after the first time) and that helped but if I went to 75 or 80 it was like a tire was still out of balance.



Today, I searched all of the sights I could find on indexing and finally, on the Roadranger site troubleshooting tractor trailer vibrations, I saw in their flowchart where the first thing they recommend is the 180* drive shaft rotation. So I came home from work and did it. Took out the rear bolts, rotated the pinion yoke 180* and bolted it back up.



Well it worked. I did a five mile at 45 mph run (smooth ) to the interstate and then let it rip. Other than road vibration from the concrete seems, the truck has smoothed out. On the section of I-75 that has been recently covered in asphalt, it was smooth to 90 mph. I turned around two exits later... ... still smooth.



I would have never believed that would work. No more vibrating passenger seat. Oo.

 

[GCroyle]

Alan,



I haven't read what you referred to, glad it helped you. But my only . 02$ is me thinks drive shafts are a science of their own and need their own special respect.



Gary

 

[GaryCarter]

Thanks for posting. Might need that some day.



I have had vibration problems on other trucks that were only solved by trueing and balancing the tires on the truck. Not many shops know how to do that any more.

 

[Alan Reagan]

I imagine that something spinning that fast does require special science. I'm really surprised at the number of weights on the shaft. Even more surprised at the number of weights on the front axle drive shaft. This is the first time I remember seeing so many.



There was a big red dot on the shaft but I didn't see any indexing mark that it corresponded to. Must have been an inspection mark. It was about 1 inch in diameter.



My brother in laws Furd has this same problem. Vibration starts around 70. I guess we will try it on his, too.

 

[RonD]

That was a smart move, make sure you paint a white stripe at the attachment point should some shop take it apart they will re-install it the same.

 

[Alan Reagan]

I will index with the stripe. It was such a pleasure driving in this morning.



I have to go to Virginia on Thursday. That's a 600 mile run up the coast. This will make it more tolerable.

 

[Alan Reagan]

I have thought about this since I did the rotation and am wondering if the problem is not balance but where the drive yoke bolts to the pinion. Could it be that it was not centered but off to one side? Is that what is causing the vibration?

 

[HEMI®Dart]

Off Topic....

Here is the degree sign if you want it °



Start w/ # 17 post.



https://www.turbodieselregister.com.../231617-drained-flushed-cooling-system-2.html

 

[Alan Reagan]

Where'd you get that? I do the best I can with the brain I got. :-laf

 

[Shelby Griggs]

Hold down the ALT key while typing 248, the ASCII keyboard code for the degree symbol, °



May only work from the dedicated number pad, not the number keys across the top of your keyboard.



SHG

 

[Alan Reagan]

°



Alt 248 works. Thanks. I would probably still use the * if I can't remember the ALT 248 trick.



Truck still riding smooth. 1200 mile round trip was a real pleasure without the vibe.

 

[TBartlett1]

When I replace u-joints I mark the flanges & all drive shaft parts before removing from the vehicle so all parts are installed in exactely the same position.

Helps prevent vibrations when there weren't any before.

 

[Alan Reagan]

I will mark mine now that the vibe is gone.