Had your drive shaft balanced lately?

[D-Day]

I had mine done a couple days ago, and it made a pretty big difference for my '73 Chevy crew cab (two piece drive shaft). Took care of the truck wobbling at around 20-25mph, and the oblongish intermittent hum at highway speeds. It'll also keep my carrier bearing from wearing out as fast.

Now all I gotta do is get better tires on the back so they don't hum/vibrate, and not mudders. Oh well...what do you expect at 80mph.

[magnethead]

that makes me wonder..what kind of hum was it? Because mine hums at highway speed, i'm not sure if it's DS or axle.

[D-Day]

It's almost sort of a shake...it's a droning hum, but it's not a steady hum, it's like out of tune or something. The reason I say this is because my tachometer on my dash shakes about every 2 seconds but not in between...so it was definitely a rotating/intermittent hum, and it doesn't do it now with the drive shaft balanced.

[albertarose]

thats exactly what I experianced with my short box big block truck the faster I went the worse the vibration ..kind of a pulsing vibration when I put it in neutral it went away ..its a two piece driveshaft I replaced the steady bearing and u joints tryed phasing it differently put the truck on jack stands and ran it in gear and watched the shaft to see if it wobbled (nothing)..checked all 4 wheels for true and ballance still nothing ..pulled the posi diff cover to look for pieces (nothing)...its gotta be the driveshaft Im thinking perhaps its lost a weight or just has a very slight tweak ..Im wondering if there is any advantage to a one piece shaft on a shorty truck ..I will post a question about this and see what is the general opinion here..

[Pyrotechnic]

Had the one in my long bed balanced and new u-joints put on. The rear end was also really sloppy so I had that rebuilt. Makes one hell of a difference. Feels like a brand new truck. It's something people often overlook but very important. One tell tale sign that your driveshaft or rear end is sloppy is when you shift from park to drive with your foot firmly on the brake and it makes a sound like "BANG!!" or you can feel the truck jerk, then there is some slack in the driveline.

[84slopwaggin]

Yeah I had that bang problem and I had the rearend rebuilt. The ring and pinion gears were wore really bad as were the spider gears. I had a vibration before this work was done and I still do now. I suspect the driveshaft needs to be balanced. The u joints were replace when the rearend was rebuilt. I don't know why they didn't balance the rearend while it was out of the truck. Mine vibrates between 40-60mph. I also have dry rotted tires so I'll replace them to see if thats not the problem, but I think its the driveshaft. I've had them do u joints before and they would balance the driveshaft as well. Its always came back smooth and black with a spicer decal on the driveshaft. I've got to save up for the wheels and tires first.