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Discussion Starter #1
Me again. Looked around forum, couldn’t really find any specific things to check. Next on my repair list is vibration that comes in around 60 MPH. Didn’t feel like tire balance but pulled all 4 and balance is perfect. Guess possible drive train issue? Just replaced both rear struts, didn’t see any worn out parts. Front feels tight up on lift. Any ideas would be appreciated. Thank you.
 

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Does it change with throttle? If so, it could be the inner CV joints. For the propshaft, there is a bearing in the middle that can cause vibration when the bushing starts to fail. Most of the time it causes noise when making sharp turns, but it can vibrate too.
 

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Discussion Starter #4
PZ, Assume you are referring to front inner? And when you refer to prop shaft, is that drive shaft to rear or shafts to front wheels? Probably not an easy way to figure out which one could be potential problem.
Emry, never dealt with a warped axle. What causes and how would I determine if warped. Dial indicator ( which I don't have) and spin? Front, back, or any one of them?
Thank you.
 

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I have a slight vibration also in my twin (02 4mo glx wagon 2.8l atq a/t) of your car RQJ.
definitely something in the drivetrain:
I can pop it into neutral and I feel it.
If I rev the engine while in neutral it doesn't change the speed or feel.
related to speed as it gets more pronounced at higher speeds.
when the car was inspected there was no play in the bearings/hubs.
All front control arms and outer tie rod ends have been replaced
Same noise on three sets of tires (original ones, new ones bought last year, winter ones on different rims that are on it now)
Seems to disappear or lessen when banking / turning towards the right (I need to test this again)

thoughts? maybe CV axle?
 

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Discussion Starter #6
I had slight vibration years ago in my Jetta which would go away with slight pressure to left so figured it was right wheel bearing so replaced and all good but this Passat has different symptoms, haven’t heard any noise but will pay closer attention, but do get vibration at 60MPH, haven’t had a chance to take on highway to go over 60. Looked last night at all bushings and control arms, tie rods, couldn’t find any play. My next step is inspection, can get one regardless but will take it to place in town who flunks for anything. Since only $12.50 here in ME. Thanks for info. Mine is also GLX 2.8
 

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The front inner CV will cause a throttle dependent vibration. It usually will change based on throttle input. Grab the axle just past the inner CV and check for vertical movement.
The prop shaft is the center driveshaft to the rear differential. If you remove the heat shield above the exhaust, you will see the center bearing and carrier. It's normal to have some play, but if the U-joint starts to fail, it will vibrate like crazy. The rear differential also has a front support bushing that goes bad, but it causes a clunk under throttle changes. You can replace just the bushing using the A6 part as VW does not list it.

My propshaft has a slight vibration above 35 and it fades away at 80. It was really bad with the poly rear diff mount. I am not certain if it's the rebuilt propshaft being slightly out of balance or the poor driveshaft spacer design that does not allow the front CV to articulate properly. With any luck, I'll look into it this summer.
 

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Grab the axle just past the inner CV and check for vertical movement.
Copy. I will try that this weekend and see where it goes.
If I do feel that movement, time to replace or is there something that needs to be tightened up?
 

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Emry, never dealt with a warped axle. What causes and how would I determine if warped. Dial indicator ( which I don't have) and spin? Front, back, or any one of them?
Thank you.
Usually hitting a deep pothole or speed limiter bumps may cause the axle either warp or go out of alignment. If that is the case (which you still have to determine) then the only way is to replace it. Also, I suggest you check for wheel alignments and make sure the both tires are balanced and have the same thread depths.
 

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If you feel it move, make certain it's the axle itself and not the flange on the trans. If it's the axle, a replacement is needed, but no rush. If it's the flange on the trans, there is a replaceable bearing on the driver's side. The passenger side may be a more of a hassle, I am not sure if the bearing is replaceable by itself.
4Mo front axles can be a bit harder to come by as they are much thicker than the FWD versions. They do interchange without issue.
 

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Discussion Starter #12
OK. Did get it to 70 today, shifting to neutral no change, decrease or increase power didn’t seem to change. Also turning left and right no change. Will try checking for play in front drive shafts again, with this info I think possibly drive shaft to rear. Feels like vibration in entire car rather then front end, no vibration in wheel. Tire Balance OK. Emry, how do I determine if a front axle is warped? Looks like fun getting to drive shaft.
98580
 

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Emry, how do I determine if a front axle is warped?
It's a bit tough while axles are mounted on the car. I think when they rebuild the old axles they place it on a flat surface to see if they tangent fully. But some shops may have machines to check on that. What you could do is to clean the front axles and let someone spin the wheel while you visually look at it. It's not a perfect method but if its damaged to the extend you can see then at least you know where you're up to. Anything, other than that the axle itself needs to be replaced.

Now a few words about replacing the axles. There are so many mixed stories about third-party axles. Lot of people I've seen are happy using them and many complain. You can get axles from Autozone for about $80 a piece. They are way more expensive at the stealerships. Given the age of the car, you must do the math and see how much you want to spend.
 

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not to sound like too much of an idiot, but will it be obvious which it is?


? or do you think these are the smaller diameter ones?
100 for a pair from rock auto
It should be fairly easy to tell. Either the axle shaft moves without the flange moving or the flange moves up and down a bit.

Those axles are the cheap solid ones. They might be ok for short term, but the hollow axles are better as there is less of a chance of vibration.

This is the only pic I have of the 4Mo front axles:
98581
 

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OK. Did get it to 70 today, shifting to neutral no change, decrease or increase power didn’t seem to change. Also turning left and right no change. Will try checking for play in front drive shafts again, with this info I think possibly drive shaft to rear. Feels like vibration in entire car rather then front end, no vibration in wheel. Tire Balance OK. Emry, how do I determine if a front axle is warped? Looks like fun getting to drive shaft. View attachment 98580
To check it, you can simply remove the center tunnel heat shield. Remove the bolts and just bend it around the exhaust to drop it down. It's easy to bend. To remove it, you have to lower the back of the exhaust, but you don't actually have to separate the pipes.
 

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Discussion Starter #16
Next time I get ambitious I will take a look at drive shaft, one problem is all the fasteners that hold heat shields are rusted out, some already gone. Same issue I had with right rear heat shield over muffler, it was just sitting on muffler. Pulled pipe and muffler off and secured best I could. Will report what I find, still in test drive mode, tonight it decided to start skipping, (engine) pulled codes so need to figure that out, runs fine on cold start but after restarting after sitting for hour it acts up. Wires, plug, coils?
98582
 

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Wires, plug, coils?
Those misfires are almost certainly from bad coil packs. Just exchange one of the coils from other cylinders and put in #5 and see if you get misfire codes. Bad coils cause shaking of the whole car.
 

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Discussion Starter #18
Looks like this only has 3 coils, is it like a Harley, Two plugs fire same time?
 

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The carrier bearing on the 4mo will cause vibrations at certain speeds when the bearing is just starting to go bad.
The one on my W8 gave a slight vibration at around 60mph, went away above 65mph and then cam back between 80 & 90mph. More pronounced at the higher speed because of harmonics involved.
 

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Looks like this only has 3 coils, is it like a Harley, Two plugs fire same time?
Yes.
The coil on the passengers side fires cylinders 5 & 3 simultaneously, center coil 4 & 2 and drivers side 1 & 6.
When one cylinder is on the power stroke (plug fire) the other is on the exhaust stroke.
 
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