Bad Vibration at 70+ MPH

onefstsnake

New Member

Nov 25, 2005

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Northern VA

Mar 13, 2009

#1

• Mar 13, 2009

• #1

Well Ive searched and have found alot of great info but nothing to solve my vibration problem.

Car is a 93 Coupe. TKO 600 trans, FMS Aluminum DS, Auburn Pro Locker, 31 Spline axles, and FMS 4.10 gears.

Vibration happens at 70mph and continues at higher speed but doesnt get worse.
No vibration under 70mph. I can put the trans into neutral and the vibration is still there. The vibration is so bad I cant see out of the rear view mirror.

Ive tried 2 sets of wheels/tires, U Joints have no play, and the wear patern on the gears looks good.

I also have a gear whine under deceleration.

Could a bad bearing in the rear cause a vibration like this?

Also how much play should there be between the splines of the axle and the internal splines in the carrier?

Any help would be awesome!

Thanks,
Ken

 

B

brytell

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Feb 5, 2009

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Rio Rancho, NM

Mar 13, 2009

#2

• Mar 13, 2009

• #2

My car is kinda doing the same thing. I heard it could be the drive shaft is out 180deg., but have not tried it yet. Have you? I checked my wheels for play when jacked up and i do have a little play in steering rack boot. does yours?

 

onefstsnake

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Nov 25, 2005

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Northern VA

Mar 13, 2009

#3

• Mar 13, 2009

• #3

I havent tried rotating the driveshaft 180* but with an aftermarket DS I wouldnt think this would do anything since the DS is balanced off the car.

Also I havent checked the steering rack, but I dont get much vibration in the wheel.

 

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brytell

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Feb 5, 2009

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Rio Rancho, NM

Mar 14, 2009

#4

• Mar 14, 2009

• #4

where do you feel the vibration the most(steering wheel, seat, shifter...)?

 

onefstsnake

New Member

Nov 25, 2005

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Northern VA

Mar 14, 2009

#5

• Mar 14, 2009

• #5

Shifter. But I can downshift or put the car in neutral and the vibration is still there.

 

Jaswir

Member

Mar 31, 2005

578

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18

Orlando, FL

Mar 14, 2009

#6

• Mar 14, 2009

• #6

motor mounts, trans mount... ive herd of rear causing the vib... might need new bearings

 

KamiKaziDK

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May 16, 2005

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Mesa, Az

Mar 14, 2009

#7

• Mar 14, 2009

• #7

Yeah, check your mounts and your seals

 

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brytell

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Feb 5, 2009

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Rio Rancho, NM

Mar 14, 2009

#8

• Mar 14, 2009

• #8

I got brand new motor mounts and trans mount and my vibration is still there, but i feel mine more in the seat and streeing wheel.

 

onefstsnake

New Member

Nov 25, 2005

792

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Northern VA

Mar 14, 2009

#9

• Mar 14, 2009

• #9

Mounts are fine as are seals.

Would a driveline angle problem cause a vibration over a certain speed and not before that speed?

 

2000xp8

SN Certified Technician

Aug 8, 2003

8,016

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194

NJ

Mar 14, 2009

#10

• Mar 14, 2009

• #10

Considering it still happens with the trans in neutral, that narrows it down to the driveshaft and back, possibly the tire balancing too.

The DS comes out easy, take it and have it checked out.
I'd also have your rear tires balanced, make sure they are doing more than just a static balance, good rims require a dynamic balancing, trust me, it makes a difference.


Brytell, your's sounds like wheel balancing and alignment, they are usually the only things that makes the steering wheel shake.

 

onefstsnake

New Member

Nov 25, 2005

792

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Northern VA

Mar 14, 2009

#11

• Mar 14, 2009

• #11

Ive tried two different sets of wheels/tires and still get the exact same vibration.

And the DS is a FMS Aluminum piece w/ good u joints. I might try just flipping the DS around and see if it helps but since its not a factory DS it wont be balanced to the car...

 

C

C&SMustang

New Member

Jul 13, 2008

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Georgia

Mar 14, 2009

#12

• Mar 14, 2009

• #12

My 93 coupe did the same thing when I bought it. It would only vibrate at speeds above 70 mph. I thought it was the tires but turns out the shocks and struts were shot. Replaced them and no problem since.

 

nine3cobra

Member

Dec 31, 2003

59

0

7

ft. walton beach FL

Mar 15, 2009

#13

• Mar 15, 2009

• #13

jack the car up and let the wheels spin slowly in first, that would be the easiest way to check. it is more than likely either the crush sleave inside the rear end that preloads the bearings for the pinion, the driveshaft is tweeked (i had the fms aluminum driveshaft get bent while stabbing a motor because it was not disconnected and it started doing exactly what your describing) or one of your axles are bent. hope it helps.

 

7upstang91

10 Year Member

May 30, 2008

936

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Florida

Mar 15, 2009

#14

• Mar 15, 2009

• #14

well the only other thing I can think of besides these if a harmonic balancer. or tie-rods. and tighting a lose strut. Make sure the Drive shaft bolts are all the way in. slightest out and you will have bad vibration.

 

T

tiptop

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Apr 6, 2008

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Mar 15, 2009

#15

• Mar 15, 2009

• #15

rearend

 

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Mr. Insurance

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Mar 15, 2009

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Mar 15, 2009

#16

• Mar 15, 2009

• #16

You have to really start looking at all the things that could possibly be causing this which would include San Diego Auto Insurance
San Diego Car Insurance
San Diego Insurance Broker




tires
wheels
driveshaft
bearings
transmission
rear end
gears


It is probably one of these, but it will take some time to narrow it down.

 

8

87AODGT

Founding Member

Jan 6, 2001

373

1

19

Toms River, NJ

Mar 15, 2009

#17

• Mar 15, 2009

• #17

I get basically the same thing you're talking about and everything was fine before I swapped to the TKO600. only thing I can really think of it being is the driveshaft since I had to change the transmission yoke to match the TKO output. I have been thinkin of just trying to flip the yoke 180* and see what happens. I would try the same thing if I were you and then you can at least rule that out

 

jikelly

20+ Year Stangneter

Jul 9, 2003

872

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Lubbock Tx

Mar 26, 2009

#18

• Mar 26, 2009

• #18

I'm also struggling with a vibration from 65 up. Thought it was the pinion angle so I changed that and it helped a bit.

But now I've got a really bad vibration above 4000 RPM in all gears under acceleration. I hate it.

I changed my u-joints, but need to drop my drive shaft and go have the balanced checked to rule that out. I suspect it might be my clutch/pressure plate, but that's just a wild guess. The clutch needs changing anyway because it slips when I get on it and shift hard into 3rd.

 

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reefbluevoodo

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May 31, 2008

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mississippi yall

Mar 27, 2009

#19

• Mar 27, 2009

• #19

pinion angle put some more degs in it!

 

MattSVTContour

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Mar 20, 2007

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Atlanta Area

Mar 27, 2009

#20

• Mar 27, 2009

• #20

jikelly said:

I'm also struggling with a vibration from 65 up. Thought it was the pinion angle so I changed that and it helped a bit.

But now I've got a really bad vibration above 4000 RPM in all gears under acceleration. I hate it.

Click to expand...

If you are sitting still with the clutch in does it do this? If so, definitely check the harmonic balancer on the crank pulley. Mine does this and I have new one on the way.