VIBRATING/SHAKING above 100MPH

2001asp

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Hey guys, I am new to the Terminator model. Had an 01Cobra for some time. Is it normal for the car to shake/vibrate at above 100MPH. I had the car up to 145MPH last week and it was shaking during deceleration. Was not sure if it was driveline or tire out of balance. Chime in if you can. Normal or not normal. Is it supposed to be smooth as butter above 100? Below 100, no issues......Smooooooth.....
 

RussZTT

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Tires out of balance, wheels not round, driveshaft not balanced. Those are pretty much your options.
 

Quagmire

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its tires, Mine had horrible vibs at 70 mph, after i turned her around. Either tire not round and or wheels are bent or not balanced.
 

Blueline

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Ok lets try this. If your feeling the shaking in the steering wheel while doing 100mph. put the car in nuetral and let it coast. Dont touch the brakes, clutch nothing. If it still shakes, its prob. something in the front end: tires, wheels out balance, wheel hubs etc.

If its shaking and you put the clutch in and it stops, may be in the driveline, trans etc.

If your feeling the shaking in the seat of your pants, rear tires, could be drive shaft / u joints, rear wheel hubs etc.

Is the wheel shaking up and down or side to side?

If your feeling the vibration when on the brakes, check your front rotors, wheel hubs.

Check these out then post back.

I had a seriously bad vibration at 80mph and up. After 3 different shops trying to balance, I found 2 flat spots on the front tires. New tires and a good shop balancing, smooth as glass.
 
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Jimmysidecarr

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Ok lets try this. If your feeling the shaking in the steering wheel while doing 100mph. put the car in nuetral and let it coast. Dont touch the brakes, clutch nothing. If it still shakes, its prob. something in the front end: tires, wheels out balance, wheel hubs etc.

If its shaking and you put the clutch in and it stops, may be in the driveline, trans etc.

If your feeling the shaking in the seat of your pants, rear tires, could be drive shaft / u joints, rear wheel hubs etc.

Is the wheel shaking up and down or side to side?

If your feeling the vibration when on the brakes, check your front rotors, wheel hubs.

Check these out then post back.

I had a seriously bad vibration at 80mph and up. After 3 different shops trying to balance, I found 2 flat spots on the front tires. New tires and a good shop balancing, smooth as glass.

Good post.

Most common cause will be tires.

If it is not the tires and the vibe seemed to come from the seat back, there is a high probability that the differential bushings at the pinon are all used up/smooshed/coming apart/collapsed/no longer any good.

When those go out the pinion angle goes out the window.
Even when brand new many of these cars have an incorrect pinion angle.

FTBR Setting Pinion Angle
 

Blueline

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Good post.

Most common cause will be tires.

If it is not the tires and the vibe seemed to come from the seat back, there is a high probability that the differential bushings at the pinon are all used up/smooshed/coming apart/collapsed/no longer any good.

When those go out the pinion angle goes out the window.
Even when brand new many of these cars have an incorrect pinion angle.

FTBR Setting Pinion Angle

Thanks Jimmy, totally forgot to include the rear diff. bushings! ha :rockon:
 

CobraBob

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I agree, Blueline's post is excellent. A lot of good diagnostic info there. I'm going to add some of it to my Terminator FAQs on my website if it's okay with you Tony.
 

MoKo_03SVT

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my car had gotten a bad "vibe" at one point, and it turns out it had slung a wheel weight (or 2) off, at some point.

it was an easy/cheap fix, thankfully.
 

Ukfox89

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i have the same steering wheel shimmy in my car. at about 60 or so the steering wheel will shimmy side to side really fast. i had the tires balanced and new rotors. it does it in and out of gear. and im pretty sure my rear shake is caus ei got 12mm bolts instead of 14mm bolts. but its not all the time. the ass shake is from time to time.
 

brian97cobra

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i had a horrible vib in vehicle around 85-120 mph. mine ended up being a pinion bearing gone bad. so i had to replace the ring and pinion and the bearings :(

but its fixed now :D
 

Fast GTO

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Don't get caught up on the FTBR solution. They are great upgrades but often not the lone cause of vibration or rear end issues.

I have the solid diff mount and it only partially solved my vibration.

At the end of the day it is a Ford with loose tolerances in teh driveline.
 

Tims97SVT

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Why don't you just get the tires checked for balance first. Also it's extremely poor advice to tell someone to go 100mph on the street and put the car in neutral to figure out where this "vibration" is coming from.
 

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