Replaced CV Axles, High Frequency Vibration(hum) at 75

[William Cody Gilliam]

I replaced my cv joint axles the other day, and then drove it 90 miles round trip to school. Drives like a dream until 75mph, then there's a new vibration, like a loud hum, almost like loud bass. It it's worst with acceleration, and it responds to it. Say, I'm just getting up to 75, it will start, set the cruise on eighty, and it's constant. Then I cut the cruise and let off the gas for a second and it cuts out until I accelerate/maintain75-80 mph. I thought it might be my old tires on the front(yes, I knew they needed replaced anyway) So I got those done today. Again, drives wunderbar until 75mph. Anyone have any ideas? Thanks in Advance!
-William

[Skoobahead]

Sounds like wheel bearing. Did you drive at those speads prior to axle replacement without any issues?

[William Cody Gilliam]

Just got back from driving it again, and I've determined that it's the engine, not the wheels. It hums/vibrates between 3,600 and 4,500 RPM. I was at the speed it started at, depressed the clutch and revved the engine--same hum with no power to the wheels. Then I got on my driveway and drove in second to 4k RPM--same vibration. So, now what? Any Ideas? This just started last week while I had the car up on jackstands for a couple of days, while replacing CV joint axles.

BTW: 99 NB GLS 2.0 AEG 5 speed "Lola"
-William

[William Cody Gilliam]

Originally Posted by Skoobahead

Sounds like wheel bearing. Did you drive at those speads prior to axle replacement without any issues?

Yeah, drove 80mph on the interstate MWF on my 45 mile commute to school.

[Stlbug]

Check the engine mounts, and the lower torque strut( dog bone).

[2005Beetle]

I thought those curly bars connected to the front axle were called vibration dampers and might have something to do with the problem. I looked it up on google images but it only shows pictures of the timing belt gear. vibration damper - Google Search

[William Cody Gilliam]

Originally Posted by Stlbug

Check the engine mounts, and the lower torque strut( dog bone).

Thank you! I will. I didn't mess with that, but I guess it's possible I could have worked it loose while I had trouble with the triple square/12 point bolts from HELL. LOL

[William Cody Gilliam]

Originally Posted by 2005Beetle

I thought those curly bars connected to the front axle were called vibration dampers and might have something to do with the problem. I looked it up on google images but it only shows pictures of the timing belt gear. vibration damper - Google Search

Do you mean the sway bar? It comes through below the axle and curves up and forward, connecting to the control arm?google sway bar

[William Cody Gilliam]

Just thought of something. I did have to disconnect the sway bar from the control arm at one point, and I know it has two bushings, but the vibration had already started before that time. (a couple days after replacement I pulled the wheel off and pulled the rotor off the spinner nut to make sure I got it on right, and I checked the inner cv bolts) Maybe that has something to do with it. Maybe I didn't get that good and tight. But it seems like that would only cause vibration in turns...

[Stlbug]

You said that is was the engine that was causing the vibration. Does it vibrate parked and reving at 3-4 thousand rpm? If it does, I was thinking that it could be one of the motor mounts that secures the engine and transaxel . There are 3 of them,one on each end of the engine and one one the bottom, the dog bone, ( the lower torque strut ). These seldom require attention, unless theres been accident or the engine needed to be jack up for some reason. If new bolts were not used in reassembly ,the mounts could loosen and the engine could vibrate within the mounts. These mounts look like they would be a pain in the butt to check. If you do make sure the rubber is all good and there is no metal on metal while your doing it.