Vibration Under Load??

[GunSupplier]

So, I have a very odd (and sometimes pretty bad) vibration under load that sometimes happens/sometimes doesn't. It is much more evident in the higher gears (3rd, 4th, 5th) under heavy boost, or going up a hill in a high gear with the revs below 3000. The car is a Tiptronic. I can't figure out what the hell the vibration is. I've had transmission mounts replaced, motor mounts replaced a week ago, all bearings other than the driver's side front have been replaced, drive-shaft was replaced about 6 months ago and everything else seems OK.

The car vibrates a bit in gear at idle, but ONLY at a complete standstill. If I let the car coast at 1mph, vibration is gone, but as soon as I come to a COMPLETE stop again, a minor vibration is felt throughout the car.

Now, I have 2 EMPI axles in the front. One is a week old, the other I replaced on my own about 6 months ago. I've read people saying EMPI is a shitty brand, and the axles are junk, etc. but I simply can't buy that an intermittent vibration under load/vibration at idle in gear would be caused by axles, it just doesn't logically make sense to me. How could a vibration that feels like bad motor mounts when completely still possibly be caused by axles? Just to be clear, there is no driveline vibration when I'm coasting.

At this point I'm starting to suspect my torque converter...?? Any input?

[jesters22]

if i keep my car in a gear i should be atleast 1 gear or 2 gears lower, and i try to accelerate i get a vibration aswell. but thats under 2k rpms.. but goes away as soon as the rpms go up. i assume its something to do with the low rpms and the wrong gear.. but sometimes im to lazy to shift when making a turn.

[GunSupplier]

^^^ Thanks for the input, but I don't think it's that. I'm never bogging the engine when it happens. It's not even really related to speed, just lots of load on the engine. In 5th gear, going about 75, if I give it some gas and get up to 5-6psi of boost, the vibration is noticeable. Same thing in 4th gear, more as the boost rises.

Any more suggestions?

[J-b5]

anytime ive seen this its been an axle issue.

for the record, i put a brand new empi axle on my passat and it started doing the same thing you are describing, two months after the install.

new axle and problem fixed.

[AudiSportB5S4]

Hmm, you have no CEL right? Vibration deff not from misfiring? Does your engine feel like it has a loss of power?

[quickglx]

center driveshaft perhaps

[GunSupplier]

Hmm, you have no CEL right? Vibration deff not from misfiring? Does your engine feel like it has a loss of power?

Nope, no CEL. I've actually never had a CEL in 3 years of ownership (but that means the car is about to explode, right? Hah.) I should change my plugs at some point just to keep up with maintenance, but there really isn't any loss of power and the last time I VAG'd, there were no misfires reported.

I'm gonna scan it with VAG again soon. I'm sure I have front O2 sensor codes, but I don't think those would lead to anything like this...?

center driveshaft perhaps

Whole driveshaft was replaced a few months ago. The issue was the same before and after.

new axle and problem fixed.

Was it an Audi OEM axle?

[xxbmxlsxx]

are all 4 tires the same on your car? if your front and rear tire diameters arent within a certain spec the awd will cause a vibration. i run staggered wheels and when i switched a front tire size vibration showed up under load, switched it back to other diameter tire and vibration gone. just a thought

alot of people have claimed vibration when not using oem axles

[YBLEGL]

Was the vibration present before you replaced that large list of parts ? Kinda tells you it wasnt the axles then or anything else since it was there before and its still there. Maybe TC is gonna take a crap soon its very comon and under load would make sense to me. Also you put in stock or really stiff engine and tranny mounts ?

[LowA4]

have you checked your control arms? Since I lowered the car a couple of weeks ago, I get the same thing. All my mounts are 034 track mounts and my axles are JHM. I am leaning towards my center shaft. Since you have replaced yours, i would look at the control arms.

[GunSupplier]

are all 4 tires the same on your car?

Same tires on all 4 corners. Bought and replaced at the same time.

Was the vibration present before you replaced that large list of parts ? Kinda tells you it wasnt the axles then or anything else since it was there before and its still there. Maybe TC is gonna take a crap soon its very comon and under load would make sense to me. Also you put in stock or really stiff engine and tranny mounts ?

To be honest, I changed the drive-shaft because of the vibration. Didn't help. The tranny mounts are stock. The engine mounts are 034 Street Density. It doesn't really make sense that it would be engine mounts anyway, as I can rev the car in Neutral and there is ZERO vibration at idle and at any point while revving. As soon as I switch into D (or reverse), there is a vibration present. It's really not awful, but it's there. My bigger concern is the vibration throughout the car when I floor the pedal while driving in gear. I'll see if I have any TC codes/engine codes later tonight.

have you checked your control arms? Since I lowered the car a couple of weeks ago, I get the same thing. All my mounts are 034 track mounts and my axles are JHM. I am leaning towards my center shaft. Since you have replaced yours, i would look at the control arms.

Yeah, my control arms look OK. One of them looks to be on the way out, but I'm sure it's not that. I know for a fact that my tie-rods are shot (and my rack may be bad too, FML) but I can't see either of those causing a vibration only under heavy load that goes away as soon as I let off the gas.

[freerider]

anytime ive seen this its been an axle issue.

for the record, i put a brand new empi axle on my passat and it started doing the same thing you are describing, two months after the install.

new axle and problem fixed.

Did the same on my left drive shaft.. removed all issues...
So J-b5 got a good point....

[mrpeterparker]

eh? I'd rule out TC unless you're in a range where the TC is locking and unlocking.

Control Arms. I had a weird "loose" vibration and it was an upper Control Arm. The bushing wasn't bad.. it was the end joint.

[GunSupplier]

eh? I'd rule out TC unless you're in a range where the TC is locking and unlocking.

Control Arms. I had a weird "loose" vibration and it was an upper Control Arm. The bushing wasn't bad.. it was the end joint.

Yeah. I'm kind of ruling out TC too because it's honestly not slipping at all, ever, and doesn't exhibit any strange behavior. It's baffling that axles could cause a vibration at idle, but I guess it's possible.

Anyone else with EMPI horror stories? Want to hear some more before I pull the trigger on replacing anything else. I'm just not too keen on buying 2 brand new OEM axles and replacing them when 2 almost new EMPI axles are already in there.

[mrpeterparker]

there's always raxles.com

[GunSupplier]

there's always raxles.com

Yeah, I know. I would most likely go through them, but it just stings to replace my OEM axles with brand new EMPI ones, and have to do it all again with something even more expensive.

Bah, curse you S4!

[megafreakindeth]

most auto tranny owners leave the car in D at a stop light and just put their foot on the brakes. on ZF trannies pre-05 at the earliest there was no function to disconnect the trans from the engine when this was being done so basiclly the car was trying to move forwards while you had your foot on the brake akin to slipping the clutch in an MT car. to prevent this from happening you have to throw the car in N at stop lights and such from the beginning of the transmissions life to keep it from shaking the car later in its life. japanese cars, notably late 90s hondas did this to an extreme extent at about 150k but no audi ever makes it 150k on stock auto trans.

additionally i have ordered 5 pairs of empi axles for the same car and stood them all next to one another and there was about 3 inches of difference per side even though each axle supposedly was the correct part number. I replaced both axles on a passat one time which resulted in an amazingly annoying vibration at idle because the axles were squeezing the diff or something stupid. I ended up having to try almost 10 combinations of the same part numbers before i found a set of aftermarket axles that didnt shake the car to death. basically this taught me that you should just keep your stock axles no matter what.

[GunSupplier]

most auto tranny owners leave the car in D at a stop light and just put their foot on the brakes. on ZF trannies pre-05 at the earliest there was no function to disconnect the trans from the engine when this was being done so basiclly the car was trying to move forwards while you had your foot on the brake akin to slipping the clutch in an MT car. to prevent this from happening you have to throw the car in N at stop lights and such from the beginning of the transmissions life to keep it from shaking the car later in its life. japanese cars, notably late 90s hondas did this to an extreme extent at about 150k but no audi ever makes it 150k on stock auto trans.

additionally i have ordered 5 pairs of empi axles for the same car and stood them all next to one another and there was about 3 inches of difference per side even though each axle supposedly was the correct part number. I replaced both axles on a passat one time which resulted in an amazingly annoying vibration at idle because the axles were squeezing the diff or something stupid. I ended up having to try almost 10 combinations of the same part numbers before i found a set of aftermarket axles that didnt shake the car to death. basically this taught me that you should just keep your stock axles no matter what.

Right, or go Raxles. I've heard nothing but great reviews of them.

I highly doubt my issue is the transmission. The vibration is quite bad under highway acceleration, and gets worse going up a hill/more load. The problem got WORSE since I replaced one factory axle with EMPI a week ago. Prior to that, I only had 1 EMPI axle, and the vibrations were annoying but not awful. After putting in the 2nd EMPI axle, the vibrations are worse, so I think I narrowed the problem down.

Are you sure you're correct about the ZF transmission thing? I find it somewhat hard to believe that a world-class German transmission manufacturer that supplies BMW, Audi and others (Jag/Land Rover, etc) didn't figure out how to avoid nasty vibration because of transmission engagement when el-cheapo cars have no such issues? Don't know if I can really buy that without some evidence.