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Discussion Starter · #1 ·
My truck started vibrating in a significant way when in 2wd (and 4wd). At first, the vibration would start at 50mph, then 40mph, and now it does it at 25mph.

The vibration/noise does not change with the engine speed.
Once it starts vibrating, it continues until I arrive at a full stop.
The vibration is strong enough that you feel in at your feet, on your seat, and throughout the truck.

All my u-joints are tight. The driveshaft was just re-tubed and balanced.
The front driveshaft has a bad ball but it doesn't spin when in 2wd.
The vacuum was checked over and it seems to be working well.
It has been fully defrosted in the shop so ice/mud build up is out of the question.

I do have new tires on the truck but I drove for 2 weeks with them on before the vibration started.

Now I only drive the truck 100m to get into the shop from time to time to figure this out. No luck yet.

Any ideas?
 

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Have a friend look under while you turn the wheels to look for play. Sounds like death wobble. What size tires did you go with?
 

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Have you checked the front end for loose steering parts? Track bar? Make sure you didnt lose a wheel weight. It must be really bad if you dont drive it, how bad does it vibrate?
 

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Discussion Starter · #4 ·
I did not check the steering components yet. I didn't suspect that to be the source of it because there is not more vibration in the steering wheel compared to the rest of the truck. The noise seems to come from the transfer case which is why I don't drive it around until I figure this out.

It's hard to describe how it vibrates. I work with experienced mechanics and they don't feel it's a wheel/tire balance issue after test driving it.

Like most of us here, they are just too busy to really dive into it so I've been investigating mostly on my own.

I'm posting here in the hopes of getting more leads as I get my hands dirty this weekend and sort this out.
 

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Maybe something in the torque converter? The first thing I would check is wheel balance.
 

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I would agree on wheel balance. It is also possible you have broken belts in your tire(s). A broken belt can get worse and act up at lower speeds. One sign of a broken belt is a spot in the tread that is not as deep as the rest. It also also possible you braked hard squealing rubber and put flat spots on your tires.
 

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you might have a damaged belt in one or more tires. It would start at 60 mph or so and as belt detoriated the issue will show up at lower and lower speeds. A buldge might show on a tire by just feeling the tread. And yes you might look at steering components also.
don't understand the transfer case diagnois.
 

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Have someone watch the track bar where it meets the axle if it moves when sitting still and steering back and forth it's shot get a new one.
 

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It tough to diagnose these things if you have multiple worn components needing replacement. Sometimes you could be chasing problems through multiple parts.
 

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Discussion Starter · #13 ·
The vibration is in the seat of my pants.
The new tires on it are Hankook winters stock size. Has less than a 1000km on them.

Tomorrow I will run without the front driveshaft, check the tires for defects, run with my summer tires, check the track bar then test drive and see if any of those things help.

I'll post my findings tomorrow. Many thanks for all the input so far.
 

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Typically steering wheel vibration is front end, seat of the pants is rear end.

As is with any troubleshooting, narrow down the culprits as best you can.

Some other thoughts - does it vibrate if you take it out of gear? Dunno if you mentioned this but did you check to see if any tires lost weights?
 

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Discussion Starter · #15 ·
It was the front driveshaft afterall! I already had a new one lined up since there was play through the components.

Now that the vibration is gone, I have a follow up question: Do I really need a new flange nut and flange seal if I change the front transfer case seal? I have a speedy sleeve ready to go onto the companion flange since there's a little leak out of the transfer case there.
 

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Discussion Starter · #16 ·
New driveshafts on the front and rear and the vibration/noise has returned!

It only starts vibrating at speeds above 50mph. That's how it started last time before it got progressively worse.

Now I can point to the transfer case as the culprit. As you might remember, I drove the truck without the front DS and there was no vibration.

As far as I know, the front driveshaft should not spin when in 2wd, is that correct? I am about to drain it and check for fillings. If I do a tear down of the t-case, what should I look for specifically that could cause this problem?

I am waiting on the factory service manual in the mail so I have not troubleshooted with the manual yet.
 

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New driveshafts on the front and rear and the vibration/noise has returned!

It only starts vibrating at speeds above 50mph. That's how it started last time before it got progressively worse.

Now I can point to the transfer case as the culprit. As you might remember, I drove the truck without the front DS and there was no vibration.

As far as I know, the front driveshaft should not spin when in 2wd, is that correct? I am about to drain it and check for fillings. If I do a tear down of the t-case, what should I look for specifically that could cause this problem?

I am waiting on the factory service manual in the mail so I have not troubleshooted with the manual yet.
It's not turning with the shaft out because the front axle is not spinning it. Sounds to me like a bearing issue in the tcase, that's what took out the seal too.
 

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Put it up on jack-stands and start it up, have a buddy operate the throttle until it gets high enough for the vibration to occur, most likely a tire or the re-tubed driveshaft, could have thrown the balance wt. they tack on when they balance the shaft. either way you should be able to track it down, with it on jack stands, because everything will be magnified with the wheels off the ground.
 

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Discussion Starter · #19 ·
Your comments had me thinking and I'm trying to wrap my head around on how the t-case works in conjunction with the front diff. I know they are vacuum actuated but I don't know what exactly happens when shifting from 2HI to 4HI. I hope to read on that tonight. Some guys at work think the diff oil might be too heavy... surely something to look into.

Chevokeeman: I can rule out tires or driveshafts as being the source of vibration because 1) there was zero vibration with the front DS off the truck and 2) there is a vibration with the old and new front DS installed.

My last post I said I can point to the t-case but could the front diff be playing a part in this?
 

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If it didn't have the vibration with the front drive-shaft out, then I think you can rule out the front differential and concentrate on the transfer case. I would crawl under the vehicle and grab the front driveshaft and check for up and down play, put it in neutral and turn the yokes, do they turn smooth or rough? Should be able to feel some roughness in the bearings if it is indeed the transfer case. Not sure if that old of a model has the chain driven transfer case, but check the back lash from the front and rear yokes, if the chain is worn out, there will be a lot of play between the front and rear yokes. Should be able to feel all the play in a worn out chain.
 
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