Bad Vibration above 65 mph - u-joint?

[Mattchu60]

Hi All. I've been driving my truck since the axle swap and I am starting to notice a bad vibration on the interstate around 65-70 mph. Its on a really smooth road which was just repaved about a month ago, so I don't believe its being caused by the road. It "feels" like a tire out of balance, but I cannot believe that since the tires and wheels are brand new less than 1000 miles ago and they were balanced before install.

There are two things I think it could be -

- First - the engine is worn out, and has a miss. I think its a burned valve or a worn lobe on the cam. Planning to address this over the winter when the truck sits more. It idles a little rough and I wonder if I am feeling the miss through the driveline when its pulling hard on the interstate.

- 2nd idea - bad u-joint? It "feels" like its coming from the front of the truck, but could this be a bad u-joint on the driveshaft? - One thought I had was to put the truck in 4x4 and remove the rear driveshaft and drive it down the interstate to see if its better. Would this be abusive to anything?

 

[woodsrider250]

#2, if they are suspect just change them....cheap, and a common wear item that will cause the symptoms you describe.

 

[Jims86]

And if it still does it after replacing the joints, unbolt and rotate the shaft 180. If it persists, you will need to have it checked and balanced.

 

[tanz45]

Hubs are locked out and front drive shaft is NOT spinning correct?

Wheel joints shouldn't be spinning then either, so can rule out all front end joints. OP mentioned it felt from front.

Verify sloppy/lose rear joints. R and R and test.

Axle swap = new rims? Steel or Aluminum? Could be slightly bent.

 

[Mattchu60]

The hubs are unlocked, so the driveshaft/axle shafts are not moving (transfercase in 2wd).

Wheels are aluminum ultra wheels. Tires are 265/75/16 BFG All-Terrains.

I'll see if a new U-joint on the rear shaft helps, one was replaced with the conversion joint when the swap was done, but the other was not touched.

 

[77 K20]

Could still be the tires also. I ordered wheels and tires last fall from Discount Tire. When they arrived 2 were not balanced- seems the weights came off while they were shipped.

This summer I bought another set of brand new tires from Costco. Balance was horrible- felt like the rear tires. Had the rears rebalanced (they were way off). Now it is better, but can notice a viberation in the front. I should have had them check all 4 at once....

So new tires doesn't mean much to me. One free and somewhat easy check is you said it feels like the front. Rotate your tires front to rear. (or have the tire shop do it when checking the balance)

 

[87sierra]

there are many things that can cause vibration like binding u-joints, worn out carrier bearing, bad outer tie rod ends. improperly balanced tires, bent rims
first of all check the u joints for binding since that is most likely problem, next check outer tie rod ends by jacking the front end off the ground with the steering wheel locked move the tries left and right and look at the tie rod end

 

[Tyger13us]

there are many things that can cause vibration like binding u-joints, worn out carrier bearing, bad outer tie rod ends. improperly balanced tires, bent rims
first of all check the u joints for binding since that is most likely problem, next check outer tie rod ends by jacking the front end off the ground with the steering wheel locked move the tries left and right and look at the tie rod end

I agree,, but i found out AFTER pulling most of my hair out??

My 4x4 anything over 60 will spin the front drive line.........

so i wired it through the inner u-joint to the cross-member and the vibration went away........

what gave me the clue was watching another square 4x4 going down the road in front of me and i could see the outer front shafts spinning?

So? i went HAY!!!,,,,,, so i got someone to fallow me @ 65-70+ to see if it was the case,, sure as ****.......

so like i said i wired the front shaft to the cross-member,, there was a hole already there and test drove and the vibration went away.......

the other thing i found that helped ALOT was to put the slip part of the shaft @ the diff and the long shaft to the trans,, that got rid of ALL the vibration that ya feel in the seet of your pants/seat.....

 

[Mattchu60]

Interesting - so maybe it is the front driveshaft spinning even though everything is unlocked.

I'll see if I can mess with it tonight.

I did change out the other u-joint on the driveshaft last night. I was mad at myself though as I forgot to mark the yoke and shaft to make sure they went back in the same spot. I just put it back together and drove it this morning on the interstate, I dont know if its in my head or not, but I think I feel a new high speed vibration, which makes me think I got the yoke rotated 180 the wrong way.

 

[MrMarty51]

Did You "Center" the u-joint ???
Drive the trunions to the outside of the yoke ???

 

[Mattchu60]

I put the clips in after pressing the cups in from the outside. I installed one clip then pressed in the other side and installed the other clip and stopped at that point.

 

[Tyger13us]

Interesting - so maybe it is the front driveshaft spinning even though everything is unlocked.

I'll see if I can mess with it tonight.

I did change out the other u-joint on the driveshaft last night. I was mad at myself though as I forgot to mark the yoke and shaft to make sure they went back in the same spot. I just put it back together and drove it this morning on the interstate, I dont know if its in my head or not, but I think I feel a new high speed vibration, which makes me think I got the yoke rotated 180 the wrong way.

it dont matter, the drive line is splined ya cant get it wrong.. unless somone did the d-line and have the ends off by 45,, cant find that key on my board,, as long as one end lines up with the other? straight ling of sight on the caps,, it aint twisted and the dude? some time that made up your d-line got it right............

Man? i really need to do a write up on "HOW a REAL front drive line is SUPPOSE TO BE!!"

i,,me,, have,, can,, do Over 100 MPH in 4 wheel drive hi,, no shake,, no wiggle, no viberaion!!!!!

and to make my point? i didnt **** my drive line and take out my oil pan ether!!!

I am very confadant that when i shift my T-case into 4 HIGH the rest wont distroy my motor by taking out my oil pan..........

yup dudes,, i made sure.............

but as ALL of ya Know? it could happen,,,,,, but it hasnt yet....

if ya doubt me? COME ON OUT and i will give ya a ride ya will never forget...... remember?

YOU have to wear the belt,, thats to keep your fat ass out of my lap when were doing 100+ in 4x4 on dirt and just one miss hap, and someone is going to get hurt.........

i need to steer you need to **** your pants and i will buy the beer......

Crazy4 kinda gets me...........

 

[Mattchu60]

Well I got all 4 tires balanced. The front shake is gone. I have a new shake - in the seat. Pretty sure that the new u-joint I installed needs to be replaced as it was very free in its movement. I'm betting I cured the original problem with the front tire being out of balance, but caused a new one by replacing the ujoint.

The shake comes and goes, only at around 65-70mph. It will be on and off for around 2 seconds at a time.

 

[89Suburban]

it dont matter, the drive line is splined ya cant get it wrong.. unless somone did the d-line and have the ends off by 45,, cant find that key on my board,, as long as one end lines up with the other? straight ling of sight on the caps,, it aint twisted and the dude? some time that made up your d-line got it right............

Man? i really need to do a write up on "HOW a REAL front drive line is SUPPOSE TO BE!!"

i,,me,, have,, can,, do Over 100 MPH in 4 wheel drive hi,, no shake,, no wiggle, no viberaion!!!!!

and to make my point? i didnt **** my drive line and take out my oil pan ether!!!

I am very confadant that when i shift my T-case into 4 HIGH the rest wont distroy my motor by taking out my oil pan..........

yup dudes,, i made sure.............

but as ALL of ya Know? it could happen,,,,,, but it hasnt yet....

if ya doubt me? COME ON OUT and i will give ya a ride ya will never forget...... remember?

YOU have to wear the belt,, thats to keep your fat ass out of my lap when were doing 100+ in 4x4 on dirt and just one miss hap, and someone is going to get hurt.........

i need to steer you need to **** your pants and i will buy the beer......

Crazy4 kinda gets me...........

Posted from hell

 

[77 K20]

Posted from hell

would be my guess