Weird Shuddering in driveline under hard acceleration?

[jesse500]

I am having a weird problem with my USP.

My car has a weird problem I cant seem to narrow down. It shudders from the driveline/I think) under hard acceleration. It happened for the first time about a week to 2 weeks ago on the highway. I was doing 120 km/h in 6th, gave it some more petal to pass a guy before lane ended, and it has 1 shudder in driveline once and then pulled fine. Then it would do it in 5th & 6th, any time I gave it more than 60% throttle. Then started in 4th/3rd under heavy accel (damn near WOT). Will not do it in 1st ever, 2nd not really either, unless I put it to the floor in boost. Car is running 21psi Stage 2 tuning file, so It pulls decently. Clutch is only 30,000km old (OEM clutch, not sure if flywheel was done). BUT clutch engages buttery smooth, and it bites with clutch petal barely off floor, hell I can roll into first on flat ground with no throttle atall. It never slips in any gear (rpm spike with no speed spike) and is crisp to shift. The Shudder almost feels mid to rear of car, and before it would only do one shudder, now it does it more, like the shudder stays until I lay off throttle. I can drive car around all day if I use 50% power or less, and it works perfect. Also feels like a tiny bit of a vibration in middle/rear of car that wasnt there before, but It could just be snow in wheels.

Could this be DMFW or hanger bearing issue? Or diff/motor/trans mounts? Driveline shudder with a google seach seems to point at clutches alot, but like I said, mine doesnt slip, and engagement is still perfect, so I'm not sure. Car has 207,400 km (128K miles).

[customa4]

How do the tires look?

[jesse500]

How do the tires look?

Damn near brand new Toyo Winters. 225/45/18 on OEM S4 wheels.

[customa4]

Have you scanned for any codes? I think the way you're explaining the problem you're losing power when you lay into the gas? If it's losing power it's not the tires, sorry for the misdirection. Might want to monitor VCDS while you drive and see if you're getting misfires.

[jesse500]

Have you scanned for any codes? I think the way you're explaining the problem you're losing power when you lay into the gas? If it's losing power it's not the tires, sorry for the misdirection. Might want to monitor VCDS while you drive and see if you're getting misfires.

Nothing on VCDS, no CEL, no misfire codes. I kind of thought of misfire, but its too much of a driveline/metallic problem. I can feel it in middle/rear of car. And its not loosing power, there is a weird noise/feeling in the driveline under power. shudder/studder is the best I can explain. It has the power, I just can't keep my foot into it, or else it keeps "shuddering". I can do 1st WOT everytime, 0 issue, 2nd WOT and it wont do it most of the time, its mostly in 3rd-6th under heavy load/accel it does it. If I do 50% throttle, zero issues.

[jesse500]

Update:

Double checked everything I could in VCDS, nothing, zero codes in any module.
But I went for a little 20km trip, and evidentally its getting worse.

it does it in 2-6th now, 1st still doesnt. And I have to feather throttle to not let it shudder. When it starts shuddering, it will not accelerate atall. Even in 5th @ 60mph, cruise set, small hills, when it automatically applies throttle, it will shudder. vibration in drivetrain is definetly there, I have to clean out wheels of salt/dirt/snow to be sure though its not from wheels.

[heywier427]

one of your front axles is about to shit the bed.

I diagnosed the same problem last night.

Been driving with your symptoms for a few weeks untill yesterday, when i couldnt accelerate at all with out the shuddering (wheels feel like theyre rapidly going left to right).

Pieces of crap only lasted 250,xxx and 50 of that was with ripped boots :)

[87supraman]

one of your front axles is about to shit the bed.

x2 Give a good look at the inner CV joints.

Sent from my SM-G920V using Tapatalk

[userbob0001]

Check your coolant flange. I haven't had an axle go bad, so I can't speak to that, but my flange leaked on the bell housing and I think it got on the clutch because I had a similar shudder until I replaced it.

[jesse500]

Check your coolant flange. I haven't had an axle go bad, so I can't speak to that, but my flange leaked on the bell housing and I think it got on the clutch because I had a similar shudder until I replaced it.

No leakage, a little oil back there from when dipstick tube was gone, but nothing bad.

[jesse500]

one of your front axles is about to shit the bed.

I diagnosed the same problem last night.

Been driving with your symptoms for a few weeks untill yesterday, when i couldnt accelerate at all with out the shuddering (wheels feel like theyre rapidly going left to right).

Pieces of crap only lasted 250,xxx and 50 of that was with ripped boots :)

x2 Give a good look at the inner CV joints.

Sent from my SM-G920V using Tapatalk

Did yours feel like the rumble/shudder was coming from the back, too? Could mine possibly be a rear CV axle? how would a blown CV make it shudder like that? usually they pop and clack, etc..... (from my past truck experience).

If it was my fronts, does anyone know if an axle from a FWD/CVT 1.8T 03 A4 would fit my 04 6 speed Quattro? and I have had a slight pull to the right/humming from the right side of the car. Not bad enough to accuse wheel bearing, but enough to know something was off. Also a bit of a shake on that front right side, I just thought it was one of my S4 wheels poorly balanced/slightly bent.

[old guy]

Interesting that your stock OEM clutch starts to engage right off of the floor. That is not typical behaviour for a stock OEM clutch. Even brand new the stock clutch engages between ½ to ¾ of the way up.

Worn axles are pretty easy to check. Just get the car up on ramps and check the lateral, rotational and up and down movement. There should be no rotational or up and down movement and a small amount of lateral movement.

[jesse500]

Interesting that your stock OEM clutch starts to engage right off of the floor. That is not typical behaviour for a stock OEM clutch. Even brand new the stock clutch engages between ½ to ¾ of the way up.

Worn axles are pretty easy to check. Just get the car up on ramps and check the lateral, rotational and up and down movement. There should be no rotational or up and down movement and a small amount of lateral movement.

Your right, right off the floor is inaccurate. I just mean, it bites very early, compared to a buddies B6 that has a clutch that we know is getting worn. At engagement, it is buttery smooth

[fast377]

My car has a similar issue. Almost sounds/feels like going over the rumble strips on the sides of the highway. Mine only does it in the lower revs under load (6th gear 2800 rpm wot as an example). I also get a little clunk on gear changes. I installed a new oem dual mass flywheel and clutch and the problem persisted. I looked at the driveshaft center bearing and it looks okay. Rear diff mount looks okay (even tried looking for movement by loading the diff with a jack). I'm leaning toward the rear half shafts. I just need to get under there again and see if I can tell anything.

Keep us posted on your findings.

[heywier427]

Welp, i have new (front) axles coming, so I will update as soon as they go in.

Nothing else will be changed except the axles.

But they are the problem, as I have diagnosed this symptom in the past.

Rumble strips are a good comparison.

You have to have your vin in front of you to look up the correct axles. Lots of split year shenanigans going on with the vag.

Im going to say they are not the same, cvt vs. qwattro.

[amgraham]

Did yours feel like the rumble/shudder was coming from the back, too? Could mine possibly be a rear CV axle? how would a blown CV make it shudder like that? usually they pop and clack, etc..... (from my past truck experience).

If it was my fronts, does anyone know if an axle from a FWD/CVT 1.8T 03 A4 would fit my 04 6 speed Quattro? and I have had a slight pull to the right/humming from the right side of the car. Not bad enough to accuse wheel bearing, but enough to know something was off. Also a bit of a shake on that front right side, I just thought it was one of my S4 wheels poorly balanced/slightly bent.

When i bought my car it had a blown inner front left cv boot that looked like it had been that way for awhile. It had a similar shudder that went away after i replaced it. Now i just need to replace my crap tires...

I doubt a cvt axle will work but should be pretty easy to cross part numbers. Also whoever mentioned the split years is correct.. my 02 had 2 possible axles and it could not be determined by the vin. There is a tag in the spare tire well that will have a trans code.. that's the one i needed. Unfortunately my tag was ripped off so i just had to order both axles and put in the one that looked most similar to mine. Still new axles were only like $60 each and really simple to change.. no reason not to do them if they look iffy.

[19jdog]

I had this same problem. It was the center bearing on the driveline. Replaced driveline and problem solved.

My money is on the driveline.

[jesse500]

I had this same problem. It was the center bearing on the driveline. Replaced driveline and problem solved.

My money is on the driveline.

You are reffering to the hanger bearing on the driveshaft, correct?

[19jdog]

You are reffering to the hanger bearing on the driveshaft, correct?

Yep. Get the car on stands and remove the protective cover. See if the rubber on the bearing is sagging and try to move it around. If it moves easily that's probably why you get vibrations.

[jesse500]

Well I feel like an idiot. Turned out to be a bad coil/coils. I swapped in 4 new BKR7E's gapped to 0.032". Didn't change, had some new Revision D coil packs kickin around, threw those in, back to perfect. I've felt misfires before, that was the weirdest misfire issue I've ever incountered. and zero engine codes for misfires.