Weird driveline vibration

[SUX2BU99]

After I swapped rear ends I noticed I have some vibration. Happens at about 50-60 MPH. It's an oscillating type of vibration. Not constant but kinda vibrates smooth-vibe-smooth-vibe-smooth-vibe every second or so. Increases with speed. I don't feel it in the wheel. Moreso in the floor so I'm thinking it's driveline or rear axle related. By 60 or so it's not so noticeable. Would this be a bent axle? Oh man I sure hope not   

What makes this more weird is that when I was taking the old drums off, I banged on it pretty hard with a 2.5 lb sledge since it was rusted on. The drum weight fell off and I guess I dented the face. After putting everything together, it was smooth. It was only after I had the drums turned and the parts store guy banged out the dent in the drum face that I noticed the vibration. I thought it was the missing weight so I bought a new 'economy' drum and put it on there. Vibe is still there. Ideas?

I have to admit I haven't been back under there to re-torque everything again since the rearend swap.

[Russ130]

I have the same vibration on my truck and have ever since I got it 15 yrs ago. I have swapped trannies, t-case, engine, tires and rims and driveshafts. So the vibration for me is definitely coming from the rearend. I'm going to be bringing it to a rearend shop shortly to have it fixed once and for all. I'll let you know shortly what the problem was as soon as I find out myself.

[SUX2BU99]

Right on! Thanks for the input. I keep wondering if it's a bent axle but how does a shop determine that except by just replacing parts and seeing if it goes away?

[zieg85]

Same thing with my 85, I had a drum out of round and replaced it.  The only things I haven't tried is 2 new or different tires and my shocks are original.  Up on jack stands the tires run true and no vibration which has got me puzzled.  My vibration is between 53-57 mph when it occurs.  Shocks are the cheapest things to try next, probably need it after 24 years...

[VileZambonie]

Check to see if your driveshaft is out of phase or has a bad u-joint. Check your u-joints and tranny mount. If it checks out ok wrap a few hose clamps around the driveshaft and see if the vibration changes.

[SUX2BU99]

Thanks guys. I guess it's easy enough to unbolt the u-joint and turn it, then re-bolt it on again to see if that helps at all. It's weird that this seemed to happen after the drum got turned but who knows.

[Russ130]

yeah I played with driveshaft phase to no avail, I also replaced the shocks with no luck there either. I figure it has to be either a bent drive shaft or something inside the rearend possibly the gearset.

[Russ130]

Update: I know it has been a while but life gets you like that at times. So anyhow to get to the topic I sent out my driveshaft for an overhaul meaning new spline shafts new u-joints and new balancing. Vibration gone!

[SUX2BU99]

Thanks for the update. What did that all cost you? I still have my vibe. It has seemed to move around some as far as what speeds it shows up. Yeah I know, how weird is that?? Still around the same range though 45-55 MPH or so. One thing I have noticed is that when I am steady-state cruising in the speed zone range that it shows up, the cyclical vibration is more drawn out. As soon as I give it some gas, the vibe gets faster. It's like the vibe is changing as the motor is torquing up and moving around?  It's like this:

steady state:  viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....

accelerate a little: vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..

And no, I haven't played around any with my driveshaft yet. I'm still trying to get the 500 miles put on my newly-installed rear end gears.

[Russ130]

It cost me $200 to get all the work done. I feel the slip joint being worn and the whole shaft being out of balance where the causes for me. I still have a small vibration but I'm pretty sure that is the balancing on the tires now. Have you noticed if you let off the gas that you get a more pronounced vibration for a second and then it goes back to the regular vibration? That was the case for me and I think that was caused by the slip joint being worn. Well at any rate when I put it in gear now it doesn't make any noise which I thought was the chain in the t-case.

[MrFiveOh]

Thanks for the update. What did that all cost you? I still have my vibe. It has seemed to move around some as far as what speeds it shows up. Yeah I know, how weird is that?? Still around the same range though 45-55 MPH or so. One thing I have noticed is that when I am steady-state cruising in the speed zone range that it shows up, the cyclical vibration is more drawn out. As soon as I give it some gas, the vibe gets faster. It's like the vibe is changing as the motor is torquing up and moving around?  It's like this:

steady state:  viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....viiiiiiiiiiiiiiiiibe....

accelerate a little: vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..vibe..

And no, I haven't played around any with my driveshaft yet. I'm still trying to get the 500 miles put on my newly-installed rear end gears.

Im currently chasing a vibrations just like this between 40-52mph. did you ever fix this issue?

[philo_beddoe]

I have the identical vibration also, i tried the hose clamp trick with a slight weight under the clamp and the vibe is much less. I'm taking dshaft in for an overhaul,,,balancing, new u joints and whatever else. Pretty confident that will correct it. Will post results.