Pulsation noise at higher speed from the back
#1
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Car: 1984 Pontiac Firebird Trans Am
Engine: V8 5.0L HO (L69)
Transmission: B&W T5
Axle/Gears: 3.73 limited slip
Pulsation noise at higher speed from the back
Hello,
When I'm driving at speeds between 100-110kph to 130-140kph (55 to 85mph), there is a rather loud "pulsation" noise coming from the rear somewhere. It goes away above 130kph. I feel a slight vibration in the seat back. It's hard to describe with words but it goes like a low toned "wooo wooo wooo".
At first I thought it could be a rear end bearing but I guess the noise would be audible at all speeds.
I'm wondering if it could be an unbalanced driveshaft problem instead.
What do you think ?
When I'm driving at speeds between 100-110kph to 130-140kph (55 to 85mph), there is a rather loud "pulsation" noise coming from the rear somewhere. It goes away above 130kph. I feel a slight vibration in the seat back. It's hard to describe with words but it goes like a low toned "wooo wooo wooo".
At first I thought it could be a rear end bearing but I guess the noise would be audible at all speeds.
I'm wondering if it could be an unbalanced driveshaft problem instead.
What do you think ?
#2
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Join Date: Sep 2008
Location: France
Posts: 588
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Car: 1984 Pontiac Firebird Trans Am
Engine: V8 5.0L HO (L69)
Transmission: B&W T5
Axle/Gears: 3.73 limited slip
Re: Pulsation noise at higher speed from the back
Nobody ? I was told on another forum it could be a brake rotor or wheel balance issue. But the wheels and tires were balanced only 600 miles ago. A mechanic friend did it, and I trust him so I doubt that could be the wheels.
#3
Re: Pulsation noise at higher speed from the back
My 86 camaro did the same thing. It's got the Borg t5 but only made the noise and vibration in 5th gear above 60 mph. I put it on blocks had a buddy speed the wheels up while I was under it (dumb I know) and the noise was coming from the tail shaft. This might help you might not just my experience with it.
#5
Re: Pulsation noise at higher speed from the back
I've got the same noise. Replacing axle bearings soon to see if it take care of the noise. Theyre really cheap to replace and relatively easy and since I'm sure they are the original bearings I might as well.
It could also be wheel balance or a bent rim. Less likely for sure, still possible.
It could also be wheel balance or a bent rim. Less likely for sure, still possible.
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theshackle
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09-17-2020 08:26 AM