diagnosing vibration under power. CV vs Ignition coil

[thelub]

I've been experiencing a pretty serious vibration under acceleration that I'm trying to diagnose. After some intense search sessions here and various other forums, I've come to the conclusion that it is either ignition coil or CV shafts. Is there a definitive way to diagnose which of the 2 it is?

Car is a 2002 XC70 with 145k on the car and 40k on a "new" motor. The motor was replaced prior to me buying this vehicle last July due to a bad sensor that blew the motor.

I get a whole car vibration under acceleration at any speed. I've had a full trans flush done and had the front control arm bushings and tie rod ends replaced with no change in the vibration. My mechanic said the CV boot was bad so they changed that. They said the axles looked fine, but I'm starting to 2nd guess his diagnosis. There are a lot of posts here that describe my problem to a T that were all caused by worn axles.

Needless to say this is a very frustrating problem. I've dropped over $2k in the last 2 months on what my mechanic called "maintenance" and it hasn't done anything to change this vibration problem. It went away for an hour after it got out of the last trip to the shop, but now the vibration is as bad as before. Before I thought I felt it in the rear of the car more than anything, but now it feels like a wheel is going to fall off. I'm leaning towards the problem being a CV shaft as it has plenty of power all the time.

One thing to note that might be important: when the engine went out, the used car dealer had to tow the vehicle. They didn't have a flat bed so they removed the drive shaft and towed it on the back wheels for about 30 miles. Could an improperly installed drive shaft cause this vibration or is it most likely a CV shaft? Should I concentrate on the front shafts? How likely are the back ones to go bad?

[ericjp]

If you power brake the vehicle it should tell you if your engine is missing under load. I'm not sure about the cv/axle alignment. Does it vibrate under acceleration at a variety of speeds or only at higher speeds?

[howardc64]

They didn't have a flat bed so they removed the drive shaft and towed it on the back wheels for about 30 miles. Could an improperly installed drive shaft cause this vibration or is it most likely a CV shaft?

Removing the propeller shaft isn't a quick job, its surprising to me they did this just to tow the car. Volvo directions calls for reinstalling the prop shaft with the exact same alignment for bolt and holes to maintain proper balance. Although I've done my without doing this without any problems.

I'd start with your last known experience where the vibration disappeared for an hour before coming back. What repair was done at the shop? Your description seems to show the vibration pattern changed from rear to "wheels feel like its going to fall off".

Does engine produce high vibration when not moving but revved while in park? Probably also a good idea to rev the engine with the car in gear while al 4 tires are off the ground to see if the vibration can be reproduced in this manner.

[parsapolis]

I had vibration right before my axle snapped on me at the u-joint. The vibration was worst when I accelerated while turning.

See if the vibration is worst when you turn left/right at slight acceleration. Be careful not to accelerate too hard or the axle might snap if it's already failing as the biggest stresses on it happen when the u-joint is spinning at an angle. If the vibration gets worse on turns then you probably have bad front axles. When my right one snapped it took out the timing belt cover, accessory belt and messed up the crank pulley.

[01V70XC5A]

I am starting to suspect that my vibe issue is axle related as the vibrations are more severe under cornering acceleration. Looks like a replacement may be in order...

[thelub]

Hey all. I forgot to post a followup to my problem. I ordered both front replacement axles off swedishautoparts.com for around $300 total. Replacing them is so simple and fast I thought I was doing something wrong! Just gotta jack up the front end and remove the bottom bolt on the shock mount. Loosen the top bolt. Remove the retaining bolt in the end of the axle. For the driver side from there all you need to do is turn the wheel all the way to one side and the axle pulls out. For the passenger side you need to remove an additional 4 bolts for the axle carrier assembly. And I thought Hondas were easy!

Replacing both front axles completely solved my vibration under throttle issue. My vibration problem occurred under power at any speed regardless if I was turning or not.