SRfastZ

i have the same damn problem right now also and im thinking its the axles and do yall get alot of wheel hop ?? i do, off of first gear i hate it =( and i have lower control arms also. A few years ago my car would wobble when ever i was going fast on the highway then i changed the DS and they fix it and now i got this problem which im sure its the axles and bearings im just waiting on my Income tax to get that **** fix

firehawk933

I am yet another victem of this irritating road vibration. Mine started after installing my 12 bolt and torque arm. My pinion angle has been reset twice with no fix. It starts about 70 and gets better around 95, which seems to be the same for everyone. I automatically rulled out the axle bearings where the 12 bolt was brand new. Short of going back to the stock torque arm, I'm not sure what to do. I can't believe with as many people having the same problem, no one has found the solution

Dragula

iTrader: (5)

I was warned before getting the Spohn TA that it would be more noisy. I'm sure the mounting point on the unibody has something to do with it. The original tranny mount was made so any vibration woulds work it's way back to the car through bushings whether engine, tranny, LCA, or Panhard Rod.

ninobrn99

iTrader: (8)

im aware of that and i knew to expect the noise, but not this much. This is excessive. More than what I should have. I do suspect the pinion angle to be a major factor. If i had a stock TA, Id see how much change that would have on things and see if it was indeed it.

Dragula

iTrader: (5)

I agree this amount of vibration is to much.

I think we should list our driveline mods to find similiarities in the problem. Add new segments if needed.

Engine Mounts: Stock
Clutch: Stock
Transmission Mount: Stock
DS: Stock
Rear DS Yoke: Aftermarket 1350 - Not rebalanced after switch
Rear End: Strange 12 Bolt w 4.11 & Eaton Diff
TA: Spohn Adj Poly Mount for long tubes
LCA: Stock
Panhard: Alstin non adjustable poly mount
Tranny output angle: 4 degrees down
Pinion Angle: 2 degrees up

firehawk933

Engine Mounts: Stock
Clutch: Stock
Transmission Mount: Stock
DS: Stock
Rear DS Yoke: Aftermarket 1350 - Not rebalanced after switch
Rear End: Moser 12 Bolt w 4.11 & Eaton Diff
TA: Spohn Adj Poly Mount for long tubes
LCA: BMR
Panhard: stock
SFC: BMR
Pinion Angle: 2 degrees up

ninobrn99

iTrader: (8)

Ram powergrip HD
RAM billet flywheel
stock motor mounts
poly transmission mount
PST 3.5" aluminum DS
Moser 9" tru trac
spohn chassis mounted TA
spohn lca's
spohn relocation brackets
spohn adj. PHB
all poly bushings
bilstein HD shocks
stock springs
im not sure what my pinion angle is now. Ill have to double check it. I know its off though.

1QUIKWS6

iTrader: (61)

I have the same vibration problems around 70mph and do have the Spohn T/A. I realize it uses a different front mounting design - but find it hard to believe that the stock T/A mount absorbs the vibrations I'm getting - it feels as if the car will tear itself apart. My mods:

I believe that my problem stems from the pinion angle - but can't be sure as I ask 10 different people how to set - and get 10 different answers...

See my latest thread on this subject:

Pinion Angle Correct?

I do know that I did NOT have the vibration problem with the previous Random Tech Adj. T/A that mounted same as stocker and Pinion Angle was set up by Strano. Item that changed in my case immediately prior to vibration was the Spohn T/A and the Pinion Angle setup by the local alignment shop...

Maybe I need to drive back to Strano to have it done correctly

-Jay-

ninobrn99

iTrader: (8)

maybe us should and let us know if it helps

1QUIKWS6

iTrader: (61)

Here is the myriad of variables I have seen for setting Pinion Angle:

Some say it is relationship between Tranny and Rear

Some say it is relationship between DS and Rear and call it 'True Pinion Angle'

Some say to measure with DS installed

Some say to measure with DS NOT installed

Some say to measure Tranny Angle from flat spot on underneath of tranny tailshaft

Some say to measure Tranny Angle at face of tailshaft where seal is located

Some say to measure Tranny Angle from Engine Oil Pan

Some say to measure Tranny Angle from Engine Harmonic Damper

Some say to measure Rear Angle from flat spot of T/A mount

Some say to measure Rear Angle from face of Pinion Yoke

Some say measure Rear Angle from flat spot underneath Rear Housing

Some say to impart negative (-) value to reading if pointing down to ground

Some do not say anything about negative or positive values for measurements

Some say to subtract Rear Angle from Tranny or DS Angle

Some say to add Rear Angle to Tranny or DS Angle

I realize that some of the statements on how to measure are the same differerence but SOMEWHERE in this mess is the CORRECT combination on how to set your Pinion Angle...

ninobrn99

iTrader: (8)

I was under the impression that the correct way is to remove the driveshaft and measure your angle from the output shaft/seal on the tranny and on the pinion yoke. I was lazy and didnt do it this way and now I have this issue, where as before I did remove the DS and didnt have any issues FWIW.

JB00SS

Engine Mounts: Stock
Clutch: (3500 stall)
Transmission Mount: Stock
DS: Stock
Rear DS Yoke: stock
Rear End: stock with 3.73
TA: stock
LCA: Stock( i have UMI's on work bench w/relo brackets)
Panhard: stock
Tranny output angle: stock
Pinion Angle: stock

JB00SS

i found out saturday that my drive shaft has been shortened. the guy who i bought the car from didnt tell me and i assume he twisted it. i bought the car with 26,000 and bone stock. it is 1.5 inches to short. it is also a few degrees out meaning it is just a hair twisted. it also has a vibration damper on the front which from what i understand none of these cars have. not 100% sure that is a true statement but everyone i have talked too so far has said the A4 and M6 shafts are the same. So with all that being said i need to buy a driveshaft. I was looking in the summit mag and seen the one the offer for 324.00??? anybody know anythign about it?

Mike2000Z28

Yeah I put that one on my car and I still have the vibration after the install. Nice piece but it didn't help the vibration we are all facing.

JB00SS

i am thinking either the summit one or Denny's. I have heard so many good things about the Denny's might give him a call here after while. Do you have any insight on the vibration damper that is on my driveshaft now? should it be there? I am trying to figure that out. Does yours from summit have one on it?

so mike what you are saying you spent money on a driveshaft that did not help in the vibration problem. But this could be my wom wom wom problem since i have found out my driveshaft is screwed...I just hate to spend $$$ and it doesnt cure it

Dragula

iTrader: (5)

JB00SS - Are you having the vibration or just noise?

Most of us have the Spohn TA, you have the stock one which may mean that the TA is not the cause.

Has anyone else had a twisted DS?

1QUIKWS6

iTrader: (61)

I'm gonna go out on a limb here and say that unless the DS IS the cause of the vibration - adding a new expensive DS is NOT going to solve the problem nor cover it up...

I've had (3) DS (2 new aftermarket and 1 stock) in the car and still have the vibration - I severly doubt I got (3) bad DS...

With the exception of JB00SS who states that there definitely IS a problem with his DS you will notice that he is also the only one that is still using the stock T/A - so in his case the DS may very well be the problem.

However,

While it does seem that most of the rest of us have the Spohn T/A (4 out of 5) I would not be so quick to decide that that specific T/A is giving us all the problem - the common factor is that all (5) have an aftermarket T/A of some mfg. - meaning that most of us had to deal with re-setting the dreaded Pinion Angle.

JB00SS

1QUIKWS6, I hope you are right and the driveshaft is my only issue. I really feel it is the reason for my noise. As for vibration, i had a little with the ES tranny mount but it really didnt bother me that much i got used to it. I just want the f**king noise gone!!! Oh I did order a new driveshaft yesterday I went with a PST for $399. It should be here by the end of the week. I am also considering prothane motor mounts and installing them this weekend along with the driveshaft, then put my ES tranny mount in along with an ES tq arm bushing i bought too. the motor mounts i want to do cause i am tired of the damn pipes hitting the floor board and the engine does shake a little more with the cam. I just want to GIT R DONE and enjoy the car i am sick and f**king tired of working on it. I just want to go on a drive with the tops out and not have a care in the world...

ninobrn99

iTrader: (8)

im right there with ya! I am running the PST 3.5" aluminum DS. I called them today about it and they do balance them in house so the likely hood of it being unbalanced is very slim... that leaves the pinion angle now.

burdie5533

I am concerned that we may have several different sources of vibraton and everyone is not having the same problem. First there are several types of vibration; static, dynamic, and resonance. Lets take a drive shaft, if it is statically unbalanced like what would be corrected with balance weights at the ends, the vibration would get progressivly worse as rpm increases. If it is dynamically unbalanced, it would be worse at a certain (drive shaft not engine). To balance for this, weights at the ends will not work. It depends on the critical frequency of the shaft and may need balance weights at the quarter points. The only way to tell this is a high speed balance at the rpm the shaft is being used and I am unsure if any of the balance shops can do this. All components have a natural frequency at which they vibrate. Although the components may be static, if something operates at this frequency, it can excite the component.
This brings me to our problem. My car vibrates at 2000-3000 rpm in any gear and also in neutral (although not as much). This is the rpm where the engine gets a little rough, and I think it is exciting my exhaust system. I haven't had a chance to check this yet but plan to wedge a 2X4 between the exhaust and the floor to change the stiffness of the exhaust to see if it changes things.
Lets go back to the discusion above. If it is a static unbalance of a drive shaft it would get worse as the speed changes. This would be car speed on the drive shaft and engine speed on the torque converter or flywheel. Bearings can cause vibrations that pulse because if there is a damage roller, it will cause vibration at some multiple of rpm and only when that roller is under load.
As far as phasing of the drive shaft, I was always taught that the transmission output shaft should be parallel to the pinion in the axle in the loaded condition so a degree down may be OK (in relation to the transmission shaft, not the ground). I would like to know how many people have modified exhaust systems and have the same vibration characteristics as me?