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Discussion Starter · #1 ·
Have 2003 5.5 Passat Wagon 1.8T with 98,000 miles; not techtonic drive. One front wheel/assembly (seems like passenger side) is giving-off a low-pitched "thumping" sound much like a flat spot on a tire might do (i.e thump, thump, etc). (1) This is a sound; no vibration felt in steering wheel or front end. (2) Thumping frequency increases with rotation speed of wheel. (3) Seems to quiet-down going uphill but could be my imagination. (4) Stops making sound above 55 mph and rides smooth. (5) Thumping sound is accentuated when coming to a hard stop (weight shifting to front). (6) No decrease when I put clutch in or coast in neutral. (7) Engaging driver's side axle makes no difference. (8) I have not elevated front end to check drive wheel assemblies while they rotate. (9) Half axles not too old; recently replaced passenger side - could be the issue.

So far:

1. Replaced all front brake rotors, calipers and pads thinking warped rotor, hung-up pads etc. No change. The existing parts did not exhibit unusual wear/defects but caliper slides were starting to show rust.
2. Replaced all tires with new Michelin Defenders; balanced at install. Rides better/rolls quieter, but still thumping noise. Was due for new tires but no unusual wear on existing tires noticed.
3. Checked all lug nuts for proper torque (89 fp).

So far I've invested about $800. This seems to leave following possibilities:

1. CV joint defective. Under warranty; can replace and see if that corrects problem. Doubt axle bolt looseness.
2. Wheel bearing defective: Would not expect at this mileage but could replace.
3. Transmission ???

Anyone have some thoughts ????
 

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Tomvw: Sorry .... unclear when said "Engaging driver's side (half) axle makes no difference." Meant "When I engage the ASR button" which I understand locks the driver's side half axle to the passenger side half axle.

Yes, suspect my recent aftermarket passenger side half axle. Its a life-warranty new manufactured hollow-shaft Duralast unit made in Mexico. Years past had go-arounds with NAPA and Advanced Auto selling Chinese units, Cordone and others, but excellent results with an Raxles OEM rebuild (now he said he's depleted his OEM VW supply). Junk yards won't guarantee I'll get an OEM if I order there. Anyone have experience with "VW OEM Parts" web site (abt $300) ??? Regardless, I'll replace it.

Is there anyway to "test" the wheel bearings ??
 

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Raxles OEM rebuild is the way to go. If you can pick up an OEM axle from a junk yard, you could make sure it is OEM.


FYI: The ASR is always on by default, when you press the button and it lights up the ASR is switched off.
The ASR does not lock the dif, it just applies brakes and reduces engine power to prevent wheel spin.
The ASR light on the dash flashes rapidly while the ASR is active.
 

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Discussion Starter · #6 ·
Its now end of October and this is current status: Now have 103,000 miles. Front end noise seems to be slightly worse; Makes the osculating/rotational low-pitched thumping noise under 70 mph, uphill, downhill, especially when cold and when braking as vehicle weight shifts forward - the harder one brakes the worse it is. Noise correlates with wheel rotation speed, in-gear or in neutral, and occurs when brakes are not being applied. Old and new tires show no flat spots. However, there are a few times when the noise disappears (???).

Amending previous notes: No vibration or shaking in steering system; Checked front end steering system; Aligned all 4 wheels (no significant adjustments necessary); Replaced the front end calipers, rotors and pads both sides; Inspected rear calipers, rotors and pads; Installed and balanced all new Michelin tires; Replaced passenger side 6 month old Chinese Duralast aftermarket half-axle with an OE rebuilt unit by Raxles of Florida; OE driver's side half axle appears okay; Checked torque on all half-axle bolts (inner and outer); Checked for interference's.

Last Resort: Replace front wheel bearings ????
 

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It is not the front wheel bearing. The bearing will "roar" when it is going bad.

I would be looking at the transmission. If there is no vibration...I doubt it is the axle or anything in the brakes. When did this sound begin? Just out of the blue or after performing some maintenance?

Z
 

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You keep switching usernames, it kind of threw me off.

Have you topped off or ever replaced the front differential fluid? The check/fill plug is just above the axle flange on the passenger side. Takes 75/w90 gear oil.
 
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