Help finding a vibration.....

[EZFEED]

OK just so you all know this is not on a deuce, this is on my Lizard.

What I've been feeling is a low pulsing vibration when I reach a sustained speed of 45mph or a little higher.
It is smooth for about 4 seconds then goes brrrrrrrrr for about 3 seconds then smoothes out again and repeats this.

Is there any trick you guys are using to find things like this?
The driveshafts are all balanced and I know this because I see the weights on them. Could this be a problem in the transmission or could it be due to a tire or something?

What do you guys do to find these problems and fix them?????
Have any of y'all balanced 2.5ton/5ton tires before?????

 

[clutch]

just an idea but is there any chance one of the brakes are warm after you drive it? ive had the same noise you describe in other vehicles and found one brake not releasing all the way. just rubs enough to build a little heat and then make the drum chatter.

 

[EZFEED]

I will look into this. Thank Ya!!!!

 

[chvss65]

push the clutch in or put in neutral when vibration is happening
if it goes away, then probably u-joints

 

[EZFEED]

Holy crap thats a good idea!

I'm writing this stuff down and will try tomorrow, I have been trying to think of ways of isolating certain parts to find this vibe and I knew you guys would have some great ideas!
Thanks!

 

[EZFEED]

One of my buddies said I should single it out and run it on 4 wheels at a time.

Seems like a good idea? Single the back then run it, if its still there, pull the backs off, if its still there, pull the fronts off, then criss cross and chain up the axles with no wheels till I found it.
Sounds OK but allot of mess I just want to get this problem eliminated if possible so if we ever have a rally down here and I have to drive for an extended period it wont bite me in the butt.

 

[chvss65]

another one, during vibration, if you turn the wheel and it goes away, probably wheel bearing, the pressure of the turning takes pressure off of the bad bearing so it quites making vibs or noise

 

[EZFEED]

I'll have to get up on the big black top road to do that but I will try it. Hopefully its not a bearing because the final dives on these portals are freak'in huge. I have a slight steering misalignment but I know its in the back, I can feel it coming from back there.

Have you ever balanced a big tire like this or does it really matter?

 

[chvss65]

would say that the low speed most of this stuff runs at wouldn't make that much difference, but i may be wrong, my deuce (avatar) isn't balanced and it runs just under 70 without vibration from being out of balance, matter of fact it runs out smoother that my Jeep Wrangler haha

 

[EZFEED]

LOL! Too cool! So your running 70mph.....wow! How did you manage that? Different ring and pinion sets?

An I would say you are right too about the vibration. I'm just being a little over cautious because I cant get specific parts in the states for it. Bearings and seals I think I can manage.

 

[rizzo]

LOL! Too cool! So your running 70mph.....wow! How did you manage that? Different ring and pinion sets?

An I would say you are right too about the vibration. I'm just being a little over cautious because I cant get specific parts in the states for it. Bearings and seals I think I can manage.

bigger tires. chase car clocked my 543 at 70mph...once.

 

[EZFEED]

Dang that must be a wild ride Rizzo and Chvss65!!!!

 

[WillWagner]

I had a vibration in the deuce at 45 to 50 MPH. All the u-joints were good, driveshafts in phase, everything I knew to check was good. I swapped the t-case from a sprag to an air shift and it went away. There might be be an issue inside things that you can't see.

 

[EZFEED]

Boy I hope not.........would you have a way of figuring that out? I was thinking of having a helper drive while I leaned out and took a look underside. Strapped in of course

 

[tm america]

finding a vibration is a process of elimination and noting changes first get it to start doing it sway truck from side to side take note of changes then accell and decell note changes then get it to do it push in clutch note changes then get it to do it and ride the brakes then slightly apply the e brake note the changes if you notice a change while swaying it the problem probably lies in the wheel or wheel bearings if it changes when accell or deccell the problem is in the driveline if change is noted while braking look into the brakes try different gears could be in the trans note changes think about what you can eliminate as the problem dont think cuz you see weights it is balanced right or that it isnt bent if no luck there rotate the tires see if anything changessorry for the long post vibrations are sonetimes hard to trace down but you dont just start throwing money at it just think it out

 

[EZFEED]

I wonder if using a dowel or rod and touching the parts will help.