High Frequency Vibration (1 Viewer)

[Old 40]

I have a weird high frequency vibration between 50 and 80 mph on the highway in my 2000 LC. I just had a shop do the tie rod ends, rear motor mount, upper control arms, CV boots, and the u joints. It also has new BFG KO3's as of last Friday. The alignment is great, tires seem well balanced, and everything feels good until I hit about 50mph. At that point there is a vibration that builds as speed increases and really becomes noticeable if I let off the gas. Like a helicopter with a flamed out engine. The only thing I saw that might be suspect is a single yoke nut on the front shaft that is obviously not OEM. Anyone have any insight into this?
Thanks.

 

[Old 40]

Also, the vibrations were not present with the 8 year old BFG 's and before the shop had it. Could I be missing something in the driveline since the truck has 263K on it?

 

[Bisho]

I think the only things you touched that would result in vibrations is the tires and U-joints. I'd start with getting the tires rebalanced. Its not unheard of for the balance to be off, or a weight got thrown off.

 

[Old 40]

I think the only things you touched that would result in vibrations is the tires and U-joints. I'd start with getting the tires rebalanced. Its not unheard of for the balance to be off, or a weight got thrown off.

I am heading back to the tire shop today to see if the balance is off. The U-joints are brand new though, not more than a hundred miles on them. With the exception of the single incorrect nut on the rear yoke, it looks correct and feels tight. Any possibility it could be wheel bearings or the carrier bearings?

 

[cruisin4bruisins]

I am heading back to the tire shop today to see if the balance is off. The U-joints are brand new though, not more than a hundred miles on them. With the exception of the single incorrect nut on the rear yoke, it looks correct and feels tight. Any possibility it could be wheel bearings or the carrier bearings?

Had similar issue, I dont think its your balance. For me it was some bad bushings and my rear sway bar being bad. Check your suspension parts, bushings, rear sway bar. Get under there and just feel around for anything loose you might be surprised what you find. If it was wheel bearing i think it would be a different feeling and you'd probably hear it. Good luck
Edit: also rotate the tires maybe its a bad tire, if you rotate them and the feeling is different then maybe its a defective tire

 

[Old 40]

Had similar issue, I dont think its your balance. For me it was some bad bushings and my rear sway bar being bad. Check your suspension parts, bushings, rear sway bar. Get under there and just feel around for anything loose you might be surprised what you find. If it was wheel bearing i think it would be a different feeling and you'd probably hear it. Good luck
Edit: also rotate the tires maybe its a bad tire, if you rotate them and the feeling is different then maybe its a defective tire

Good points. I have to go over to the tire shop today anyway (chipped each and everyone of the wheels powdercoat), so I will have them rotated. The suspension is all new, but maybe a bolt is loose or something?

 

[cruisin4bruisins]

Good points. I have to go over to the tire shop today anyway (chipped each and everyone of the wheels powdercoat), so I will have them rotated. The suspension is all new, but maybe a bolt is loose or something?

very possible, my right rear side of my sway bar was completely unbolted and toast, i also had to replace a couple bushings that were bad. After that the issue was like 95% gone

 

[Live to Ski]

doesn't take much to make a spining mass go out of balance.

If i remember correctly, a change in u-joints (spefically clocking) can throw a drive shaft out. maybe even the mentioned bolt.

Also, if your rig has any kind of suspension lift, that affects drive shaft angle and can cause vibration. check to see if the angles at both end are the same. I'm sure the board has bad angles figured out.

If run out of solutions, might want to have the drive shaft balanced.

 

[Old 40]

Ok, I will run through the underside this weekend and report back. I ordered an OEM driveline bolt kit and will replace the offending nut when it gets here. I do have an OME 2 inch lift, but it was doing great before the u-joints were replaced. The shop did the u-joints, rear motor mount, tie rod ends, CV boots, and upper control arms at the same time. I replaced the old BFG KO2's with new KO3's last Friday, but I can't honestly say if the vibrations were any better or worse. The truck drives great and is in alignment, but I want to make sure there is not a small issue that will become a big issue down the road. This truck is for my son, so I want it to work for him.

 

[Old 40]

Update on this issue. I finally got back under the truck to replace the non OEM nut on the front shaft, and then noticed another non OEM nut on the other end of the front shaft, along with several other nuts missing washers and one that was so lose I could turn it with my fingers. I am going to order a set of OEM nuts/washers and see where this goes, but the weight difference between the OEM and non OEM nuts was right at 40 grains. Doesn't seem like much, but I am thinking it is. Also, with the quality of work I have seen so far, the u-joints may not have been installed correctly.
More to follow.

 

[Import Driver]

Update on this issue. I finally got back under the truck to replace the non OEM nut on the front shaft, and then noticed another non OEM nut on the other end of the front shaft, along with several other nuts missing washers and one that was so lose I could turn it with my fingers. I am going to order a set of OEM nuts/washers and see where this goes, but the weight difference between the OEM and non OEM nuts was right at 40 grains. Doesn't seem like much, but I am thinking it is. Also, with the quality of work I have seen so far, the u-joints may not have been installed correctly.
More to follow.

This is why I have trust issues.

 

[Live to Ski]

Update on this issue. I finally got back under the truck to replace the non OEM nut on the front shaft, and then noticed another non OEM nut on the other end of the front shaft, along with several other nuts missing washers and one that was so lose I could turn it with my fingers. I am going to order a set of OEM nuts/washers and see where this goes, but the weight difference between the OEM and non OEM nuts was right at 40 grains. Doesn't seem like much, but I am thinking it is. Also, with the quality of work I have seen so far, the u-joints may not have been installed correctly.
More to follow.

on a rotating item, doesn't take much weight to throw off the balance. especially if it located a distance of the spin axis, which joint flange bolts are. Might be a good idea to make sure all mounting hardware are identical (weight wise).

 

[AlpineAccess]

Is the vibration in the steering wheel? Seat? Both?

You'll feel CV and front wheel vibration more in the wheel. You'll feel driveline vibration more in the seat and trans tunnel but also in the wheel.

Wheel bearings are unlikely to cause a vibration, but with the quality of work you're describing I would check they tensioned them properly.

Using mismatch bolts on driveline definitely could cause a vibration. If they did not phase the driveshaft when reassembling as well that could do it. Try pulling the driveshaft they worked on and put the CDL on and take it for a drive.

 

[Old 40]

Ski, excellent point and I am replacing all the nuts, washers and bolts on the rear shaft, and the nuts and washers on the front with OEM. It looks like the shafts were marked with a paint pen, so I am hoping they were at least remounted correctly.
Alpine, the vibration feels like it is coming through the whole truck, but not specifically in the shifter or steering wheel. It becomes much more pronounced if I let off the gas at highway speeds. I am going to drop the front shaft this evening and see what happens. The wheel bearings haven't been messed with as far as I know.

 

[GerLC100]

I guess you'd hear the wheel bearings at this point when you feel vibrations in the whole car ^^

 

[Old 40]

I guess you'd hear the wheel bearings at this point when you feel vibrations in the whole car ^^

I was thinking that too initially, but it wasn't an issue until I got it back from the shop. The old tires (BGF KO2's) weren't that bad or noisy before it went to the shop, so I don't think that is the culprit. The shop did the CV boots, which took 4 weeks because they didn't have the boot clamp tool, upper control arms, rear motor mount, tie rod ends, and the u-joints. They previously did an OME lift kit as well. I have found several bolts that were loose, non OEM parts (even though I provided OEM parts to the shop) and generally substandard work. At this point, I will just work through the issues and get the wheels/tires rebalanced by a competent shop once I replace the hardware on the shafts.

 

[LJE]

Does the vibration frequency track with driveshaft speed? Could be u-joints - may have been damaged upon install?

 

[AlpineAccess]

Ski, excellent point and I am replacing all the nuts, washers and bolts on the rear shaft, and the nuts and washers on the front with OEM. It looks like the shafts were marked with a paint pen, so I am hoping they were at least remounted correctly.
Alpine, the vibration feels like it is coming through the whole truck, but not specifically in the shifter or steering wheel. It becomes much more pronounced if I let off the gas at highway speeds. I am going to drop the front shaft this evening and see what happens. The wheel bearings haven't been messed with as far as I know.

Whole truck shake after the work they did is either driveshaft balance/u-joints or tires based on what we're talking about here! Happy Hunting

 

[baltistyle]

Im sure this is not the issue but easy to check. Do you still have your frame weight/s?

 

[Old 40]

Good morning, yes, the frame weight it still hanging there. As I have zero experience with replacing u-joints myself, is there a way to visually inspect that they have been installed correctly? The vibration is not a gradually increasing "shake", but a something that reminds me of a rotor or centrifuge that is out of balance. The faster it spins, the more vibration it transfers to the vehicle, and it increased when I let off the gas, and is slightly less under acceleration. I will mess with is after tomorrow. Happy Thanksgiving and thanks for your insight!