Help diagnosing vibration

[brianrride]

Tires don't typically make a deep rumbling sound like you explained...they will wobble, shake, and slap the road...but that deep rumbling vibration is usually a driveline issue. My money is on those axles - I would almost guarantee it. Good luck man!!

 

[aphil]

UPDATE: So, I took it by my mechanic and he does not think the remaining "noice/vibration" is a tire issue. He said it is a called a "harmonic". He is going to look at U-joints and motor mounts and one other thing. Did not seem to think it was from the new left front Axle, but I'm bringing it back next week for them to really dig into it and figure out what's causing the "harmonic." Could a harmonic still be caused by the aftermarket axle?

 

[Julian Stead]

I agree with the mechanic, get the motor mounts and transmission mounts checked or just change them as they go hard and compress with age even if they haven't failed totally. Grease the driveline also. I get this vibration when the weather gets colder, I think it is the transmission mount which I am going to change soon along with motor mounts.

 

[PDPerry]

UPDATE: So, I took it by my mechanic and he does not think the remaining "noice/vibration" is a tire issue. He said it is a called a "harmonic". He is going to look at U-joints and motor mounts and one other thing. Did not seem to think it was from the new left front Axle, but I'm bringing it back next week for them to really dig into it and figure out what's causing the "harmonic." Could a harmonic still be caused by the aftermarket axle?

Sorry. Was gone a few days.
What does the original repair order say - if anything - about the part used?
Can't emphasize enough... having gone through this about 8 years ago.
That axle has got to be OEM. Except for the serious replacement parts that some folks here use, aftermarket parts will not work.
One test that I just recalled: Have your mechanic disconnect both front shafts. Lock your transfer case. Take it for a spin.
If it still shakes, it ain't the shafts.
If it don't...

 

[reznunt]

Honestly, I have no idea if they are doing "Hub Centric" vs a "Lug centric" balance. I assumed, being a professional tire shop, that they would know when to use what. I've always bought from Discount Tire for nearly 15 years and have never had any issues until now.

If they put the wheel and tire on the balancer spindle and stick a big cone into the front of the bore and tighten it down, then it's a hub centric balance.

But reading hearing your update it doesn't sound like a tire issue anymore.

 

[aphil]

Update: Mechanic checked the U-joints and motor mounts and a few other things and said everything looks fine. He said he found some part (can't remember what) of the driveline that was in serious need to be greased up. They lubricated everything and gave it back and said drive it a while and see if that helps. I've put 150 miles on it with no improvement.

Wife says its not very noticeable, but I can definitely notice it. The tire balancing has gotten rid of most of the vibration, but I still feel a minor pulsing vibration at the same time the harmonic happens between 48 and 65mph.

I asked the mechanic if the new aftermarket axel could be causing that and they said if it was the axel it would be causing a more noticeable vibration. Is this true?

I'll be taking the 100 in for new OEM shocks all the way around in a few months and will have them disconnect both front shafts and lock the transfer case while they are in there to see if that solves the problem.

 

[AmrikiQatar]

I had a similar problem prepping for a 6k km road trip.
Started with new tires, like you.
Chasing it down and cleaning up the former owner's neglect, replaced 2 bent rims, replaced both front axles, both rear axle bearings.
Still unresolved.
Made the shop remove the two rear axles and recheck the bearing job.
Fortunately the machine shop is literally across the street, so I hung out to watch.
They suggested putting the axles on a lathe to see if they were bent.
One was indeed bent.
Hit a junkyard, twice, both those bent also.
Bought a new axle and still had some vibration.
My other mechanic took out the front drive shaft and....problemo solvo
Drove it more than 10k km without that front shaft and no vibration at all.
Wound up being a combination of bent left rear axle and bent front drive shaft...

 

[aphil]

PROBLEM SOLVED! Tires. Yes, it was the tires. After a long conversation with my mechanic, who I trust, we really felt like the most logical thing that could be causing this was the tires since I did not notice it until the new tires were put on and from the fact that with each balance job (3 total) the problem was reduced. Talked to Discount tire and they agreed that it was reasonable to try a new set. They admitted that the LTX m/s were a discontinued tire and that the ones on my truck were over a year old and any new ones they ordered were going to still be over a year old. So, they agreed to order a completely new set of the brand new Defender M/S tires. This was the tire I originally had wanted but it was not available in stock size a month ago when I needed them.

New tires went on today and the vibration and harmonic are completely gone. In addition, the truck is no longer pulling to the right as it had been ever since the first set of new tires went on which I had not even begun to investigate.

A few things I've learned:
1. Dont change your tires on the day you pick up your truck from having lots of maintenance done on it. If I had waited a few days it would have been easy to pinpoint the problem

2. "new" Old stock tires can cause vibration and harmonic problems even when stored correctly and even if the tire shop says they are in perfect shape. Mine were almost a year and a half old :-(

3. This forum is invaluable as I am not mechanical and would have never imagined the tires could have been an issue after 3 balance jobs. Thanks to threads I read here and everyones input, this problem was solved at no cost to myself.

Thanks!!