Driveline Vibrations---Possible Driveshaft Issues?

[sewlow]

Another thing, if the lug nuts get smoked down with an impact you can warp rotors and drums.

I knew there was something I forgot to mention! Good call.
It doesn't take much to warp those rotors & drums by over torquing the lugs.
I don't trust torque sticks.
...or the guy that says his gun is 'calibrated'.
I've had work done where the wheels had to be re-n-re'd by someone else.
I could feel it. I had a suspicion.
Impact gun.
Get home & check the torque on one wheel, just outa curiosity.
1 lug @ 60 lbs, 2 lugs @ 75 lbs, 1 @ 80, 1 @ 120!
Five chances and not one right.
What are the odds of one of 20 being right?
Didn't bother with that. It would just p!ss me off. Retorqued them all. 90lbs.
With a torque wrench, in increments. 60/75/90. Probably a bit OCD, but it does make a difference.

 

[1998_K1500_Sub]

I don't trust those torque sticks.
...or the guy that says his gun is 'calibrated'.

Yeah, I can't count the number of times I've watched the tire guys bang on the lug nuts with an impact wrench and then "check" them with a torque wrench...

Yeah, sure, the wrench "clicks" immediately on every nut, so the torque must be “right”.

“How can it not be right?” is their logic.

Then I try to explain to them the proper procedure and get a blank stare.

Overall I've had rather good luck in this regard at Discount Tire (most, but not all times they got it right). Some of the Mom and Pop shops, not so lucky. Regardless, I trust none of them. If I'm thinking ahead I take a torque wrench with me and re-torque them in the parking lot (which pissed off the mgr at the Discount Tire in Flagstaff, AZ one visit, he told me I couldn't "work" on my car in their lot).

@sewlow: I torque them in increments / star pattern too.

 

[alignman88]

All good suggestions but that’s the issue that causes wasted time money and frustration. Guessing and loading the shotgun full of guesses and pulling the trigger at it. You need to find a REAL repair shop, or friend at a dealer with access to one, that knows how to use an EVA Meter. Electronic Vibration Analyzer. It’s is a tool with a loooong cord with a force transducer at the end. As you move it closer to the source component the amplitude of disturbance will increase, all done while driving. The display unit show which order of vibration you are looking for, and the hertz frequency it’s exhibiting. Another good dealer tool is a Reed Tachometer kinda does the same thing just different process. There’s another tool I’m drawing a blank on right now.

Everything that rotates will have a different order. Tires are usually a 1st order vibration-one disturbance per revolution between 8-15 hertz. Propshaft/driveline are either a 2nd or 4th order disturbance (going off poor memory) I haven’t used it in so long.

Around 2009-2010 when I held an instructor/R&D position at Hunter Engineering Co. I built a vibration diagnostic course and held two events for heavy duty reapair shop owners because this type deal is a time and money killer. Zero people attending had even heard of it and they were all the best of the best in the industry. Some attended both sessions. Personally I’ve diagnosed tons of stuff with an EVA meter. It will find differential issues, tire issues, driveshafts, crankshafts, camshafts and I’ve even identified bad motor mounts that caused vibration after a clutch job.

Good luck, again ask around at dealerships for guys that know it well and maybe you can get them to do a little moonlighting work.

 

[1998_K1500_Sub]

... an EVA Meter. Electronic Vibration Analyzer. ... The display unit show which order of vibration you are looking for, and the hertz frequency it’s exhibiting. Another good dealer tool is a Reed Tachometer

The EVA, and some diagnosis methods worth reading about, are mentioned in the 1998 GMT400 FSM, Volume 1, starting at pg. 0-85 to pg. 0-142, in section "Vibration Diagnosis and Correction". It's worthy of review.

I know I've seen the Vibrating Reed Tachometer mentioned in FSMs too but I didn't see it in the 1998.

The 1998 manual and others are available for download, here:

GMT400 CK Service Manual Project

GMT400 CK Manual Project - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMT400 CK Manual Project The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

67-72chevytrucks.com

 

[letitsnow]

After reading everything, I guess I won't spend money on new tires yet. I might get the driveshaft done ....can't hurt, but I am just boggled that it just appeared after a rear brake job. It might go up for sale when I get it back tomorrow. I am going to look at GMT 800 platforms. The novelty of having a 400 isn't worth it to me if it isn't drivable above 60 mph....FML, this is depressing LOL

I can relate, but you will probably regret it.

When I was younger and less patient, I took big $$$ losses on 2 vehicles due to vibrations while driving. A powerstroke e350, and 1997 z28 convertible. I spent over $5,000 on each trying to fix the problem. No success. I sold them. I regretted it both times.

Keep working at it.

 

[Erik the Awful]

Have you tried unbolting the driveshaft, turning it 180° and bolting it back on?

Stop going to Discount Tire. Apparently, they hire untrained/inexperienced staff.

This is every business now. Training costs money, and it's far cheaper to just throw employees into the fire and hope they learn. The average consumer is too stupid to know the difference anyways, so what will it hurt?

Yeah, I can't count the number of times I've watched the tire guys bang on the lug nuts with an impact wrench and then "check" them with a torque wrench...
Yeah, sure, the wrench "clicks" immediately on every nut, so the torque must be “right”.
“How can it not be right?” is their logic.
Then I try to explain to them the proper procedure and get a blank stare.

It's not like people read the instructions that come with their torque wrench. I had to teach the other members of my race team how to properly use a torque wrench after I watched more than one of them torque lugnuts and either do the above or give the wrench little more after it had clicked. I'm pretty sure there are a few people reading this thread and thinking, "Oh, crap! I'm doing it wrong."

Torquing is somewhat overrated/overthought. If you don't torque, there's a chance your work can come undone or you can warp what you're bolting down. That's it. Using a torque wrench is insurance against that. Still, if it's needed, it needs to be done right.

When it comes to wheels, aluminum wheels are fairly resilient to torquing errors. Stamped steel wheels tend to bend when torqued unevenly. I have absolutely no reservations about using torque sticks on either, so long as I keep the air pressure and my trigger pulls consistent.

 

[BBslider001]

All good suggestions but that’s the issue that causes wasted time money and frustration. Guessing and loading the shotgun full of guesses and pulling the trigger at it. You need to find a REAL repair shop, or friend at a dealer with access to one, that knows how to use an EVA Meter. Electronic Vibration Analyzer. It’s is a tool with a loooong cord with a force transducer at the end. As you move it closer to the source component the amplitude of disturbance will increase, all done while driving. The display unit show which order of vibration you are looking for, and the hertz frequency it’s exhibiting. Another good dealer tool is a Reed Tachometer kinda does the same thing just different process. There’s another tool I’m drawing a blank on right now.

Everything that rotates will have a different order. Tires are usually a 1st order vibration-one disturbance per revolution between 8-15 hertz. Propshaft/driveline are either a 2nd or 4th order disturbance (going off poor memory) I haven’t used it in so long.

Around 2009-2010 when I held an instructor/R&D position at Hunter Engineering Co. I built a vibration diagnostic course and held two events for heavy duty reapair shop owners because this type deal is a time and money killer. Zero people attending had even heard of it and they were all the best of the best in the industry. Some attended both sessions. Personally I’ve diagnosed tons of stuff with an EVA meter. It will find differential issues, tire issues, driveshafts, crankshafts, camshafts and I’ve even identified bad motor mounts that caused vibration after a clutch job.

Good luck, again ask around at dealerships for guys that know it well and maybe you can get them to do a little moonlighting work.

I have never heard of this. I'll make some calls today. I am going to pick it up and take a breath and hope I can get it figured out. I may throw some other cheap used tires, but "good" tires on there and see if it remains. i know the rear is bouncy and off kilter when seeing it run up on the lift, but he also said "the driveshaft vibrates like hell at 60" LOL....sheesh, wears me out.

 

[BBslider001]

I can relate, but you will probably regret it.

When I was younger and less patient, I took big $$$ losses on 2 vehicles due to vibrations while driving. A powerstroke e350, and 1997 z28 convertible. I spent over $5,000 on each trying to fix the problem. No success. I sold them. I regretted it both times.

Keep working at it.

Yeah, you are probably right. I plan on it....as much as I have time and money for. At this point,i want to figure it out just for the principle of the matter and not let it conquer me. I am $3500 in, but those were repairs needed and not at all for the vibration issue....front end and rear axle/brake job. I'd lose for sure.

 

[BBslider001]

Have you tried unbolting the driveshaft, turning it 180° and bolting it back on?

I have not yet, but I will this weekend when I do it to check ujoints as well. I may just take it to get it balanced too. Can't hurt.

 

[OutlawDrifter]

After reading everything, I guess I won't spend money on new tires yet. I might get the driveshaft done ....can't hurt, but I am just boggled that it just appeared after a rear brake job. It might go up for sale when I get it back tomorrow. I am going to look at GMT 800 platforms. The novelty of having a 400 isn't worth it to me if it isn't drivable above 60 mph....FML, this is depressing LOL

It's frustrating tracking this stuff down. Sometimes it's good to walk away for a week or two and come back with a fresh perspective(difficult, believe me I know).

If you part with it now, you'll be in the hole and then starting over with zero'ing out another rig.

I chased a vibration in a K5 that I never did find, I was the only one who could feel it, but it was there. Changed ALL of the ujoints, balanced the shafts, it had new tires, wheels were checked, etc. I ended up parting with it, and made good money, but if I would have kept it an extra year into the covid-era prices, I could have doubled my money on it.