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Mysterious intermittent chasis vibration - Feels like driving over rumble strips
I've been chasing down this vibration problem for almost 3 years now on my 2002, 2-door, 4WD Blazer with all the optional offroad equipment. I cannot figure out the problem.
The vibration feels like a balance problem. Like the wheel balance is off. But I know the wheel balance is fine. I badger my auto tech about them all the time and the shop has just gotten very annoyed at me about this.
So is it in the driveline somewhere? All four wheel bearings have been replaced. Front half-shafts have been replaced. New heavy duty Bilstein gas shocks, Full suspension rebuild. New HT tires. Everything new except for the transmission, driveshaft, and rear end.
This past weekend, I was doing some brake inspection trying to chase down another noise problem, and I noticed some play in the front wheel hub. I took them off and the rubber o-rings that came with these brand new Detroit Axle hubs had disintegrated. (Don't recommend Detroit Axle at all!). I went around from auto parts store to store looking fro o-ring replacements, and the guys at the counter all said that they're not sold separately. In fact some hubs don't come with them all at. They said it was an improved design not to have them. So I took the bad o-rings off and ran the hubs like that and it feels marginally better, but whole vehicle still feels like it's shaking pretty bad.
I was reading this article from ETC about the issue. If it's not tires (which I'm going in to get the balanced check... again...), then it has to be drive shaft or transmission. https://www.ericthecarguy.com/driveline-vibrations/
There's no play in the u-joints, but they're still the factory set. Blazer just hit 180k miles today. Should I just replace the u-joints anyway?
Should I take the driveshaft in for a balance check?
Can the transmission cause balance issues and vibrations?
I have been having transmission issues lately where it feels like the gears are grinding when it shifts.
It started feeling like this after I had changed what fluid was left in the oil pan when I was solving this other problem: https://blazerforum.com/forum/2nd-ge...55-mph-102944/
I just started reading about torque converter lockup shudder. Could that be the problem?
I have driven this bazer of low fluid before without realizing it. I talked about this in my 'RPM surging between 45 and 55 MPH' post.
What all "optional off road equipment" do you have? Could be something with one of those options. After all you have done trying to find what is causing the vibration, I would be trying to find a shop that can put it on a rack, similar to dyno test rack, that will let all four tires roll while strapped down. You might be able to find the culprit.
What all "optional off road equipment" do you have?
Bilstein shocks and the Eaton G80 automatic locking differential 7.625. It has most of what the ZR2 trim does- interior, wheels, suspension, etc... minus the fender flares and the spare tire carrier.
I have since then replaced the factory shocks with another set of Bilsteins.
The differential has been making noise lately ever since I change the gear oil last year. But that was something I did after this vibration problem started happening.
This vibration problem started happening on another set of tires I bought new fo rthe Blazer when I first bought it. No mechanical work had been done on the Blazer since I first started driving it. The first time this vibration started happened, I took it to Pep Boys to rotate the tires and the vibration went away. When it came back a second time around the time another rotation was due, I took it back to Pep Boys for a rotation, and it started vibrating worst than before. Eventually one of the techs told me that the inside tire tread was cupped from bad shocks. So I replaced the shocks (they were due) and bought new tires. But the problem only slightly went way after that. Since then I've been on this long journey rebuilding almost everything on this Blazer to make the vibration go away.
I've been reading about "TC lockup shudder". Could that be the problem here?
The tc locks up around 45-50 mph on normal acceleration. When does the vibration start speed wise?
Above 60 MPH. Normally around 65. Others have said it's u-joints but I can't detect any play in them at all and my mechanic confirmed there's no play. I'm thinking about changing them anyway because they're still factory.
Bit of history behind this Blazer: it spends 90% of it's time on the highway traveling at 65 MPH on average. It's always been a long distance communter averaging 500 miles / week over the past 3 years.
I think I may have found the issue with this vibration. The inner CV axle has a bit of play in it, but I can't tell if this is an acceptable amount or not. I recorded a video on it. https://www.dropbox.com/s/98pjc8sohw...51333.mp4?dl=0
Ride was feeling pretty rough on today's drive averaging 70 MPH on the highway. I'm convinced it's inner CV axles causing this shimmy.
I'm looking into want needs to be replaced. I found this video where this guys is replacing inner seals fo rthe CV axles.
I've browsed through my Haynes repair manual trying to figure out if there's a bearing too that nees to be replaced, but I can't find any info on it.
Has anyone done this work and can confirm it, or is the seal the only thing to worry about?
08-03-2021, 01:28 AM
Mysterious intermittent chasis vibration - Feels like driving over rumble strips
