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Jazzydub
2013.07.10, 10:07 AM
I recently installed a stage 3 suspension refresh kit from ECS along with a new GKN passenger side axle. Between 4,000-5,000 rpm I am getting a vibration resonating through my whole car most noticeable at 4,500. What could be causing this. Everything was torqued to spec and nothing looks off. I have read a few different threads on other sites from other people with similar issues after replacing a passenger side axle. Most bought a cheap axle from Napa or an Empi that is solid and not hollow like the OEM axles. I can't say for sure that the GKN is hollow or solid but it looked exactly like the one that was removed in diameter and seemed to be the same weight. Has anyone ever experienced this before or have a solution? I was thinking that I may need some sort of ring around the axle shaft that I have seen on some axles and that some have said is specifically to dampen vibration.

benny_mech
2013.07.12, 11:22 AM
If it's an axle problem, I'd expect the vibration to be at a specific vehicle speed, not RPM. In other words, if you experience the vibration at 4.5K rpm in 3rd and 4th gears, then it's engine speed dependent, and not vehicle speed dependent.

Jazzydub
2013.07.12, 13:22 PM
It's most certainly engine speed dependent which is what's so odd about it. It does it in neutral as well but it's far less noticeable. I'm going to put my original axle back in and see if it changes. It's like a harmonic vibration instead of something wobbling. It's strange. The only reason I'm leaning toward the axle is I came across a few different threads of people having the same issue after replacing the passenger side axle with a solid axle. Something about the hollow axle absorbs the vibrations where the solid one just passes it along to everything else. I'm hoping to dig into it this weekend. Maybe get it on the lift and rev it up to 4.5k and grab the axle and see if it stops or can be felt. While not in gear of course. :P

benny_mech
2013.07.12, 17:47 PM
There's no way it's an axle problem if it happens when you're stopped. Axles don't absorb vibration, that's the job of the harmonic balancer and engine mounts. You haven't removed the crank pulley for any reason, have you? Remind me what kind of car this is? Any chance the clutch or flywheel is on it's way out? Does it have a dual mass flywheel?

Rabbit 16v
2013.07.13, 11:46 AM
If it was an automatic, it very well could be an axle problem. However, GKN is OEM and rarely have issues. Of course we dont know what car he is talking about so its possible... :P

Jazzydub
2013.07.14, 14:53 PM
2003 20th ae. Clutch and flywheel have been replaced by the fine gentleman above. Replaced with a duel mass. Doesn't seem to to it in neutral like I first thought. Only when in a gear and moving. More noticeable on deceleration. Haven't had a chance to swap the axle yet. Unless it's just the new bushings mixed with the stage 1 dogbone creating vibration at 4.5k.

Rabbit 16v
2013.07.14, 17:51 PM
swap axle back and see what happens. I am rather dubious that a GKN axle would cause this, but anything is possible.

Jazzydub
2013.07.15, 08:41 AM
Same. It's why I get the GKN axles. I had no issues when I replaced my driver side. Hopefully I can get it up on the lift this week if he ever gets his Mercedes done.

benny_mech
2013.07.15, 15:48 PM
If it was an automatic, it very well could be an axle problem. However, GKN is OEM and rarely have issues. Of course we dont know what car he is talking about so its possible... :P

You've got to explain to me how an axle that isn't turning is a source of vibration.

P.S. GKN is British. They are also an aircraft parts supplier, and I get to personally deal with their unholy clusterf*ck of a trailing edge A350 spar design on a daily basis. /rant

benny_mech
2013.07.15, 15:50 PM
2003 20th ae. Clutch and flywheel have been replaced by the fine gentleman above. Replaced with a duel mass. Doesn't seem to to it in neutral like I first thought. Only when in a gear and moving. More noticeable on deceleration. Haven't had a chance to swap the axle yet. Unless it's just the new bushings mixed with the stage 1 dogbone creating vibration at 4.5k.

Replaced a dual mass with another dual mass?

Any chance the axle is hitting /rubbing the front sway bar?

Does anything change with clutch pedal in vs. out when in neutral?

Jazzydub
2013.07.16, 06:27 AM
Yes, the stock duel mass flywheel was replaced with a stock duel mass flywheel. My sway bar hit my old axle all the time but never did this. Only did it while turning right into a driveway. This one hasn't hit at all yet as I raised the car after wearing a groove in my old axle. I'll have to see if it does it while in neutral or with the clutch in while moving and holding it a 4500k.

Rabbit 16v
2013.07.16, 20:49 PM
You've got to explain to me how an axle that isn't turning is a source of vibration.

P.S. GKN is British. They are also an aircraft parts supplier, and I get to personally deal with their unholy clusterf*ck of a trailing edge A350 spar design on a daily basis. /rant

since we didnt know what car, an automatic in D while stationary puts load on the axle. I have seen TDI passats with bad inner CV joints vibrate so bad at a stop that you cannot see out of the rear view mirrors. GKN may be british, but its still OEM and the best CV joint you can purchase for these cars.. I can admit that I have only installed maybe one GKN complete axle. we usually remove the axle and replace individual joints as needed.

benny_mech
2013.07.17, 10:12 AM
The GKN thing was just a rant, I'm sure the different divisions don't even talk to each other.

I can see how a diesel stopped in drive could vibrate pretty bad. It makes sense that those vibrations are transmitted to the axle, and if the joint is loose, it could make it worse. The motor is the source of the vibrations, but how they get transmitted down the axle would make a difference in felt vibration.

Sorry for derailing your thread, Jazzy. :P

Jazzydub
2013.07.17, 11:50 AM
No worries. I do seem to feel/hear it while moving with the clutch pedal in whether in neutral or not. I just need to get it up on the lift and inspect everything we did and check re-torque all the bolts.

Jazzydub
2013.08.03, 13:54 PM
Finally swapped the axle for the old one and the vibration is completely gone. Feels/sounds like a different car. Now the question is what was causing it. Is the axle bad or is it due to being solid. The plot thickens.

Rabbit 16v
2013.08.04, 18:29 PM
bad axle

joel
2013.08.04, 22:10 PM
bad how? horribly balanced?

Jazzydub
2013.08.05, 06:52 AM
Not sure that it's a balance issue since the vibration seems to be harmonic instead of an physical shaking. Seems like engine vibration transfering through the solid axle with no dampening ring on it. The short side isn't long enough to create the hum. I'll be sending the axle back to German Auto Parts so they can take a closer look at it. Anyone ever seen a CV boot collapse like the air got sucked out of it? The inner was like that when we took it off.

benny_mech
2013.08.05, 14:53 PM
I wonder if it got hot, excess air bled out, and then cooled?