Chasing down vibrations at freeway speeds with UMI/Strano parts
08-19-2013, 09:31 PM
#81
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
next time im on my uncles alignment rack (which will be in a month or so, doing front LCA bushings [bolts frozen in back, hard to order new ones]), I will set it like that and report back
10-01-2013, 10:29 PM
#82
This is all very interesting, and I believe it may be my vibration problem.
My theory is that my vibration relates to the welding of 2-point UMI subframe connectors -- Speed Inc. welded them on a two post lift -- SFCs should always be welded on a four-post lift, suspension at rest. Could this create a change in the way the shaft sits due to stiffening and reducing natural factory body flex?
Inputs appreciated.
My theory is that my vibration relates to the welding of 2-point UMI subframe connectors -- Speed Inc. welded them on a two post lift -- SFCs should always be welded on a four-post lift, suspension at rest. Could this create a change in the way the shaft sits due to stiffening and reducing natural factory body flex?
Inputs appreciated.
The angles they spoke about in the previous posts are with in range, the only thing i would caution is to also check the Driveshaft angle. when you talk in terms of the U-joint angles is the difference between the two parts not what each is set at. SAE states that there are 3 angles under a single shaft system you have the Trans, the shaft and the diff. these 3 will create 2 "operating angles" or what the joint is going to and from. the rule here is no greater than 3 degrees and no more then .5 off from one end to another.
so as long as the driveshaft is at Zero yes this would be correct.
so as long as the driveshaft is at Zero yes this would be correct.
10-02-2013, 11:15 AM
#83
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,604
Likes: 0
Received 6 Likes
on
6 Posts
One easy thing is to swap wheels F/R on both sides
and see if you now get front shimmy instead. Wheel
balance can still be had, with tires that are out of round.
Then try and dope out whether the vibration frequency
like wheel speed, or driveshaft speed. About a 3:1
difference in "pitch".
By my calcs 70MPH wheel speed ought to produce a
~ 16Hz note if it's wheel related and driveshaft would
be low audible, ~50Hz or so, but maybe there's a 2X
factor there for the U-joint bind symmetry so even
higher?
Anyway if you feel it in your gut, probably wheels and
if it's more like a lumpy hum, then driveline.
and see if you now get front shimmy instead. Wheel
balance can still be had, with tires that are out of round.
Then try and dope out whether the vibration frequency
like wheel speed, or driveshaft speed. About a 3:1
difference in "pitch".
By my calcs 70MPH wheel speed ought to produce a
~ 16Hz note if it's wheel related and driveshaft would
be low audible, ~50Hz or so, but maybe there's a 2X
factor there for the U-joint bind symmetry so even
higher?
Anyway if you feel it in your gut, probably wheels and
if it's more like a lumpy hum, then driveline.
03-06-2014, 03:12 PM
#84
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
bumping this. I am FINALLY doing my front LCA bushings and I will be tackling this again. I still have a vibration over 80, so I am going to try matching the angles like Kevin97ss said...
Will report back
Will report back
03-07-2014, 05:59 PM
#85
TECH Enthusiast
Join Date: Jul 2007
Location: Central,NJ
Posts: 563
Likes: 0
Received 0 Likes
on
0 Posts
04-19-2014, 10:05 AM
#87
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
So here is my situation. I set my angles to the above.
IN GEAR, CRUISING with my foot on the gas, there is literally no vibration.
IN GEAR, FOOT SLIGHTLY on the gas in 5th/6th gear, i can feel/hear this whirring noise... but it goes away if it give it more gas.
CLUTCH PEDAL IN/NEUTRAL, I can feel the vibration.
ugh. ive had 2 transmissions, 2 rears, 2 driveshafts....
IN GEAR, CRUISING with my foot on the gas, there is literally no vibration.
IN GEAR, FOOT SLIGHTLY on the gas in 5th/6th gear, i can feel/hear this whirring noise... but it goes away if it give it more gas.
CLUTCH PEDAL IN/NEUTRAL, I can feel the vibration.
ugh. ive had 2 transmissions, 2 rears, 2 driveshafts....
04-20-2014, 12:56 PM
#89
TECH Apprentice
Great thread!
Yesterday I was about dead set on buying a bunch of new rear suspension parts, since I'm upgrading to a 4.10 gear anyway. I was going to buy new rear LCAs and Panhard bar, replace bearings and u joints. Then I thought, well, I could also get a torque arm too while I'm back there.
Then I read this post, and now I'm gunshy about the whole thing. I have Bilstein shocks and Strano springs on all 4 corners and have no vibrations anywhere.
Maybe a silly question, but was the torque arm to blame (before the angle changes) for all these vibrations? And how much does a torque arm really help? Mine's not a DD or a track car, but something fun I want to drive on nice days, but I might take it to a track once a year or so, if that.
Also, another side question, all other things the same, would everyone, who was able to fix their vibrations by adjusting angles, have been SOL had they purchased NON-adjustable torque arms?
Yesterday I was about dead set on buying a bunch of new rear suspension parts, since I'm upgrading to a 4.10 gear anyway. I was going to buy new rear LCAs and Panhard bar, replace bearings and u joints. Then I thought, well, I could also get a torque arm too while I'm back there.
Then I read this post, and now I'm gunshy about the whole thing. I have Bilstein shocks and Strano springs on all 4 corners and have no vibrations anywhere.
Maybe a silly question, but was the torque arm to blame (before the angle changes) for all these vibrations? And how much does a torque arm really help? Mine's not a DD or a track car, but something fun I want to drive on nice days, but I might take it to a track once a year or so, if that.
Also, another side question, all other things the same, would everyone, who was able to fix their vibrations by adjusting angles, have been SOL had they purchased NON-adjustable torque arms?
04-20-2014, 01:50 PM
#90
I have something similar. I get the vibration reliably when going say 35-40 MPH about 1100-1300 RPMs, when I give it gas it goes away or when the RPMs are higher and peddle is further down. If I tap the brake, the lockup is disengaged and it goes away but comes back w/foot on the gas. To me if feels like driveline, but the aluminum ds can transfer noise too...
I have been told it could be the clutch in my torque converter, or a trans solenoid, but it has happened with two torque converters and the new one is a 3200 stall Yank, and I have new solenoids as part of a TSI Racing trans build/rebuild. I also had the driveshaft replaced by a driveline specialty shop, noise is still there.
I have the stock TA, so no real pinion angle adjustments, and the bushings at the trans tail seem to be ok and TA is not bent from what I can see.
I also just added a tube of this:
http://www.lubegard.com/~/C-230/Dr.+...t+Shudder+Fixx
in case it is actually a trans shudder, could take 35-100 mi. to circulate their tech support says.
I have been told it could be the clutch in my torque converter, or a trans solenoid, but it has happened with two torque converters and the new one is a 3200 stall Yank, and I have new solenoids as part of a TSI Racing trans build/rebuild. I also had the driveshaft replaced by a driveline specialty shop, noise is still there.
I have the stock TA, so no real pinion angle adjustments, and the bushings at the trans tail seem to be ok and TA is not bent from what I can see.
I also just added a tube of this:
http://www.lubegard.com/~/C-230/Dr.+...t+Shudder+Fixx
in case it is actually a trans shudder, could take 35-100 mi. to circulate their tech support says.
So here is my situation. I set my angles to the above.
IN GEAR, CRUISING with my foot on the gas, there is literally no vibration.
IN GEAR, FOOT SLIGHTLY on the gas in 5th/6th gear, i can feel/hear this whirring noise... but it goes away if it give it more gas.
CLUTCH PEDAL IN/NEUTRAL, I can feel the vibration.
ugh. ive had 2 transmissions, 2 rears, 2 driveshafts....
IN GEAR, CRUISING with my foot on the gas, there is literally no vibration.
IN GEAR, FOOT SLIGHTLY on the gas in 5th/6th gear, i can feel/hear this whirring noise... but it goes away if it give it more gas.
CLUTCH PEDAL IN/NEUTRAL, I can feel the vibration.
ugh. ive had 2 transmissions, 2 rears, 2 driveshafts....
04-20-2014, 08:38 PM
#91
I think it's pretty common to adjust the TA to the driveshaft, when in fact the driveshaft angle does not make any difference.
04-21-2014, 11:01 AM
#92
On The Tree
Join Date: May 2011
Location: Cleveland (216)
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
I have a similar issue with "driveline vibration", over this weekend i changed my broken trans mount (A4 car) and the torque arm bushing. original trans mount was in two peices, is this normal? 
, i installed the energy suspension torque arm mount part#3-1111g (torque arm is factory), also i did the pro-thane poly trans mount part#7-1604-bl, those part numbers wont be exact but the pictured part on summit racing are the same. anyway after i swapped those out, with some prying and aligning on the trans cross member i finally got the trans mount in. had to do the same on the torque arm (prying and aligning with a long punch) had a tough time getting it all together and now i have a vibration, especially on the freeway, my 10-bolt is on its last leg (again), but has never had the vibration like it has now. by reading i would assume the trans and diff need to be realigned after these bushings?
, i installed the energy suspension torque arm mount part#3-1111g (torque arm is factory), also i did the pro-thane poly trans mount part#7-1604-bl, those part numbers wont be exact but the pictured part on summit racing are the same. anyway after i swapped those out, with some prying and aligning on the trans cross member i finally got the trans mount in. had to do the same on the torque arm (prying and aligning with a long punch) had a tough time getting it all together and now i have a vibration, especially on the freeway, my 10-bolt is on its last leg (again), but has never had the vibration like it has now. by reading i would assume the trans and diff need to be realigned after these bushings?
04-21-2014, 12:11 PM
#93
Get rid of the poly vibration transmitters! 
For example:
http://www.ipdusa.com/products/5666/...t-bushing-soft
"polyurethane bushings are firmer than the stock rubber parts they replace and can transmit additional vibration in some cases. Especially if the motor mounts and or transmission mounts are worn. When you replace the worn out rubber mount, now much of the load is supported by the new stiffer bushing and this can often lead to unwanted vibration, especially at idle on models equipped with automatic transmissions. It’s important to make sure that your other mounts are in good condition to avoid unwanted vibration."
For example:
http://www.ipdusa.com/products/5666/...t-bushing-soft
"polyurethane bushings are firmer than the stock rubber parts they replace and can transmit additional vibration in some cases. Especially if the motor mounts and or transmission mounts are worn. When you replace the worn out rubber mount, now much of the load is supported by the new stiffer bushing and this can often lead to unwanted vibration, especially at idle on models equipped with automatic transmissions. It’s important to make sure that your other mounts are in good condition to avoid unwanted vibration."
I have a similar issue with "driveline vibration", over this weekend i changed my broken trans mount (A4 car) and the torque arm bushing. original trans mount was in two peices, is this normal? , i installed the energy suspension torque arm mount part#3-1111g (torque arm is factory), also i did the pro-thane poly trans mount part#7-1604-bl, those part numbers wont be exact but the pictured part on summit racing are the same. anyway after i swapped those out, with some prying and aligning on the trans cross member i finally got the trans mount in. had to do the same on the torque arm (prying and aligning with a long punch) had a tough time getting it all together and now i have a vibration, especially on the freeway, my 10-bolt is on its last leg (again), but has never had the vibration like it has now. by reading i would assume the trans and diff need to be realigned after these bushings?
, i installed the energy suspension torque arm mount part#3-1111g (torque arm is factory), also i did the pro-thane poly trans mount part#7-1604-bl, those part numbers wont be exact but the pictured part on summit racing are the same. anyway after i swapped those out, with some prying and aligning on the trans cross member i finally got the trans mount in. had to do the same on the torque arm (prying and aligning with a long punch) had a tough time getting it all together and now i have a vibration, especially on the freeway, my 10-bolt is on its last leg (again), but has never had the vibration like it has now. by reading i would assume the trans and diff need to be realigned after these bushings?
04-22-2014, 06:43 AM
#94
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
I have a torque arm with the relocation cross member. I was thinking maybe that is to blame? Its just such an effin WEIRD vibration I can't figure it out.
OT but... BTW, I also removed my poly/poly LCAs... put in boxed stockers with 1LE bushings, and OMG!!! what a difference driving. I don't get a headache if I hit a slight imperfection in the road anymore
OT but... BTW, I also removed my poly/poly LCAs... put in boxed stockers with 1LE bushings, and OMG!!! what a difference driving. I don't get a headache if I hit a slight imperfection in the road anymore
04-22-2014, 05:55 PM
#95
Launching!
Join Date: Mar 2011
Location: Charlotte NC
Posts: 261
Likes: 0
Received 0 Likes
on
0 Posts
this is a standard response we give to allot of customer with shaft issues like this, this car did not have a 2 piece shaft but i do know the shaft spinning next to a Torque arm can cause a harmonic, i have seen it since the 3rd gen cars . hope this helps
Harmonics
You see the rubber bushings in a car are there to remove harmonics from the cabin, harmonics are caused by the engine firing in pulses and the firing turns the crank, but not smooth like an electric motor, it speeds up everytime the spark plug ignites the
fuel, this is why the engine has a harmonic damper on the front to kind of smooth this action. when you change from rubber to solid or poly mounts it will sometimes re-introduce the harmonic back in the cabin (the reason rubber is used is to make it quiet)i have been asking under scrutiny why a stock 2 piece will not do this as much as a single one and its simple. the center of the driveshaft that is supported but a by a real soft rubber hanger. its hiding this,shaft is still moving around but the rubber is soaking it up. put a solid rubber there and it would change this tremendously. its kind of masking but its still there, when you put a single shaft in there is nothing hiding the center moving around so its transfered to the ends (think of a tunning fork, hit one side and the other moves
not because its out of balance but because a sound it being transmitted thru it) Hope this make sense
Harmonics
You see the rubber bushings in a car are there to remove harmonics from the cabin, harmonics are caused by the engine firing in pulses and the firing turns the crank, but not smooth like an electric motor, it speeds up everytime the spark plug ignites the
fuel, this is why the engine has a harmonic damper on the front to kind of smooth this action. when you change from rubber to solid or poly mounts it will sometimes re-introduce the harmonic back in the cabin (the reason rubber is used is to make it quiet)i have been asking under scrutiny why a stock 2 piece will not do this as much as a single one and its simple. the center of the driveshaft that is supported but a by a real soft rubber hanger. its hiding this,shaft is still moving around but the rubber is soaking it up. put a solid rubber there and it would change this tremendously. its kind of masking but its still there, when you put a single shaft in there is nothing hiding the center moving around so its transfered to the ends (think of a tunning fork, hit one side and the other moves
not because its out of balance but because a sound it being transmitted thru it) Hope this make sense
05-12-2014, 12:34 PM
#96
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
this is a standard response we give to allot of customer with shaft issues like this, this car did not have a 2 piece shaft but i do know the shaft spinning next to a Torque arm can cause a harmonic, i have seen it since the 3rd gen cars . hope this helps
Harmonics
You see the rubber bushings in a car are there to remove harmonics from the cabin, harmonics are caused by the engine firing in pulses and the firing turns the crank, but not smooth like an electric motor, it speeds up everytime the spark plug ignites the
fuel, this is why the engine has a harmonic damper on the front to kind of smooth this action. when you change from rubber to solid or poly mounts it will sometimes re-introduce the harmonic back in the cabin (the reason rubber is used is to make it quiet)i have been asking under scrutiny why a stock 2 piece will not do this as much as a single one and its simple. the center of the driveshaft that is supported but a by a real soft rubber hanger. its hiding this,shaft is still moving around but the rubber is soaking it up. put a solid rubber there and it would change this tremendously. its kind of masking but its still there, when you put a single shaft in there is nothing hiding the center moving around so its transfered to the ends (think of a tunning fork, hit one side and the other moves
not because its out of balance but because a sound it being transmitted thru it) Hope this make sense
Harmonics
You see the rubber bushings in a car are there to remove harmonics from the cabin, harmonics are caused by the engine firing in pulses and the firing turns the crank, but not smooth like an electric motor, it speeds up everytime the spark plug ignites the
fuel, this is why the engine has a harmonic damper on the front to kind of smooth this action. when you change from rubber to solid or poly mounts it will sometimes re-introduce the harmonic back in the cabin (the reason rubber is used is to make it quiet)i have been asking under scrutiny why a stock 2 piece will not do this as much as a single one and its simple. the center of the driveshaft that is supported but a by a real soft rubber hanger. its hiding this,shaft is still moving around but the rubber is soaking it up. put a solid rubber there and it would change this tremendously. its kind of masking but its still there, when you put a single shaft in there is nothing hiding the center moving around so its transfered to the ends (think of a tunning fork, hit one side and the other moves
not because its out of balance but because a sound it being transmitted thru it) Hope this make sense
05-13-2014, 02:49 PM
#97
Launching!
Join Date: Mar 2011
Location: Charlotte NC
Posts: 261
Likes: 0
Received 0 Likes
on
0 Posts
05-13-2014, 03:18 PM
#98
TECH Addict
iTrader: (6)
Join Date: Jul 2007
Location: Ringoes/Flemington, New Jersey
Posts: 2,858
Likes: 0
Received 3 Likes
on
2 Posts
I'm ready to drive my car off a cliff... I have a post in the LT1 section, it'll give you a run-down on what I've done. ask me anything!
My Post:
I've posted a few threads about this, but all lead to a dead end. I am about to drive my damn car off of a cliff at this point.
I have this driveline vibration over 70MPH. I managed to tone it down, but it is still there.
It is completely non-existent when I am in gear driving. If I let my foot off the gas, you can KIND OF feel it, but not really.
If I SHIFT INTO NEUTRAL or PUSH THE CLUTCH PEDAL IN, you can feel it bad. It is in your butt and it feels like the driveshaft is going to fly out of the car. Again, over 70MPH.
What I have done:
Tried 2 different T56 transmissions
Tried 2 rear ends (first one was fully rebuilt minus axles)
I replaced my torque arm, but I CANNOT REMEMBER if the vibration was present with the stock torque arm. Stock one was cracked, so I dont have it anymore.
Tried an LS1 alum driveshaft, and I have my stock steel one balanced with new U joints. that is currently installed
Tried poly/stock rubber trans mount.
My trans angle is -3.1 degrees (pointing down)... so I had my rear set to +2.65 and -3.2. Both angles were about the same, but at -3.2 it fixed it while in gear. Now it is only there with the clutch engaged/trans in neutral.
Engine off/on doesn't change a thing.
I am at such a god damn loss... help"
Wheels are straight... road forced and balanced.
New flywheel, clutch, etc. But i have a feeling its not on the engine side.. it is something from the output shaft of the transmission and back.
I have rotated the driveshaft on the rear... again 2 different driveshafts same issue. splines on both yokes were fine and output shaft looks good. again, 2 different tranmissions, same issue.
I am leaning towards the torque arm relocation X member/torque arm being the culprit... I cannot remember if the stock T/A had the same vibration, was so long ago.
