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#1
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Growling and humming from the rear
My first guess is another wheel bearing but I wanted to see if there is another possibility. The only reason I am wondering is the strange behavior of the noises. At 40ish MPH the sound is kind of a growling/moaning noise and is strongest when coasting down a hill. At 70ish MPH the noise is a high pitch hum. What is most strange is that the hum fades in and out on a regular period. It is almost like the beating you get when you pluck two strings of a guitar that are supposed to be the same note but are slightly off from each other.
So is the bearing still the #1 suspect or can it be something else?
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Tony 1996 Polo Green Subaru SVX LSi, 168,XXX miles, Redline D4 ATF, Redline 75W90 gear oil, K&N HP-4001 Oil Filter, Mobil 1 5W50 FS (3qt) and 5W30 High Mileage (4qt) Oil Blend, Motul RBF600 Brake Fluid, AC Delco A975C Air Filter, NGK BKR6EIX-11 plugs, Centric Rotors, Power Stop Evolution Carbon Fiber Ceramic Brake Pads 2005 Gray Acura RL, 165,XXX miles, Redline D4 ATF with Lubegard Platinum Protectant, Mobil 1 5W20 High Mileage Extended Performance Oil 2009 Red Toyota Venza, 123,XXX, Mobil 1 5W30 High Mileage Oil 1992 Red Ferrari 348 ts, 82,XXX, Redline everything |
#2
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Re: Growling and humming from the rear
if it's not your wheel bearing it could be your rear diff or your rear axle is out of balance.
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#3
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Re: Growling and humming from the rear
Anyone else have any comments on this?
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Tony 1996 Polo Green Subaru SVX LSi, 168,XXX miles, Redline D4 ATF, Redline 75W90 gear oil, K&N HP-4001 Oil Filter, Mobil 1 5W50 FS (3qt) and 5W30 High Mileage (4qt) Oil Blend, Motul RBF600 Brake Fluid, AC Delco A975C Air Filter, NGK BKR6EIX-11 plugs, Centric Rotors, Power Stop Evolution Carbon Fiber Ceramic Brake Pads 2005 Gray Acura RL, 165,XXX miles, Redline D4 ATF with Lubegard Platinum Protectant, Mobil 1 5W20 High Mileage Extended Performance Oil 2009 Red Toyota Venza, 123,XXX, Mobil 1 5W30 High Mileage Oil 1992 Red Ferrari 348 ts, 82,XXX, Redline everything |
#4
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Re: Growling and humming from the rear
My open R160 4.444 rear diff is on its way out...... sound familiar
Tapani |
#5
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Re: Growling and humming from the rear
I had a bad rear diff that was making noise that got louder with speed and it had a vibration that could be felt. When that happened I could distinguish that it was not a wheel bearing but I was not entirely sure.
I would have a shop check them on a lift, they can listen with a scope while someone brings it up to speed while on the lift. Should be quick for them to diagnose.
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1992 LSL ebony pearl 170k - Thank you Ron Mummert Reading Box of Wine Car ----------------------------------- 1992 SVX LSL 5-Speed Sold at 180K 2019 1995 SVX Lsi Polo Sold at 118K 2007 Last edited by Sean486; 11-10-2011 at 07:28 AM. |
#6
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Re: Growling and humming from the rear
My RR bearing went recently. Sounded a lot like what you describe.
If you can get someone else to drive and sit in back you should be able to hear if its coming from one side or the other. Thats what I did anyhoo. I'm guessing if it's the diff youd get an even tone sitting in the middle and a pleasant rumble in the jockeys. |
#7
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Re: Growling and humming from the rear
Yeah, I am not getting any noticable vibrations. And it sounds like the noise is coming primarily from the right side but I could be wrong on that. There are other noises, like a faint very high pitched whistle or whine that seems centered but it is unrelated as far as I could tell.
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Tony 1996 Polo Green Subaru SVX LSi, 168,XXX miles, Redline D4 ATF, Redline 75W90 gear oil, K&N HP-4001 Oil Filter, Mobil 1 5W50 FS (3qt) and 5W30 High Mileage (4qt) Oil Blend, Motul RBF600 Brake Fluid, AC Delco A975C Air Filter, NGK BKR6EIX-11 plugs, Centric Rotors, Power Stop Evolution Carbon Fiber Ceramic Brake Pads 2005 Gray Acura RL, 165,XXX miles, Redline D4 ATF with Lubegard Platinum Protectant, Mobil 1 5W20 High Mileage Extended Performance Oil 2009 Red Toyota Venza, 123,XXX, Mobil 1 5W30 High Mileage Oil 1992 Red Ferrari 348 ts, 82,XXX, Redline everything |
#8
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Re: Growling and humming from the rear
Driving it on a lift and listening with a mechanic's stethoscope to the different possible points will narrow it down really quick.
The really bad wheel bearing on my blue car was actually enough to cause a wobbly/vibratey feeling. For a while I actually thought I had a bad axle because of it. But it was extremely bad, and had been bad for a very long time too:
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'94 Laguna Blue LSi ~159k.......JDM ultra short-geared 3.900 STi Version 7 6-speed w/ Cobb shortshifter, ECUtune 244,8.1mm/256,9.1mm i/e cams, group N motor mounts, '97 grille, JDM clear corners, Momo JDM Legacy GT steering wheel, apkarian's LED tails, silver STi BBS wheels, PWR radiator, redstuff pads f/r, drilled/slotted rotors, bontragerworks rsb #18, Koni/GC 450f/375r coilovers, Megan Racing adjustable lateral links, KMac c/c plates, Stebro exhaust, ECUtune 1v5, Optima battery in the trunk where it belongs. Turbo project '97 Ebony LSi ~137k #036.......Power mode mod, JDM clear corners, BBS wheels. AUX/pocket mod Now a mod "over there" ............Photo album |
#9
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Re: Growling and humming from the rear
Quote:
THE EVIL WHEEL BEARING RETURNS!!! KILL IT WITH FIRE. |
#10
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Re: Growling and humming from the rear
Wheel bearing(s) gets my vote. I suppose rear differentials do fail, but consider the odds.
I noticed when I had a front wheel bearing going bad that the sound varied depending on how the suspension was loaded. Sometimes I couldn't hear it at all. Other times I just turned-up the stereo. dcb |
#11
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Re: Growling and humming from the rear
Quote:
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Tony 1996 Polo Green Subaru SVX LSi, 168,XXX miles, Redline D4 ATF, Redline 75W90 gear oil, K&N HP-4001 Oil Filter, Mobil 1 5W50 FS (3qt) and 5W30 High Mileage (4qt) Oil Blend, Motul RBF600 Brake Fluid, AC Delco A975C Air Filter, NGK BKR6EIX-11 plugs, Centric Rotors, Power Stop Evolution Carbon Fiber Ceramic Brake Pads 2005 Gray Acura RL, 165,XXX miles, Redline D4 ATF with Lubegard Platinum Protectant, Mobil 1 5W20 High Mileage Extended Performance Oil 2009 Red Toyota Venza, 123,XXX, Mobil 1 5W30 High Mileage Oil 1992 Red Ferrari 348 ts, 82,XXX, Redline everything |
#12
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Re: Growling and humming from the rear
Please have them check the hub. I'm replacing my bearing again after less than 10,000 miles because of a worn hub.
Gene
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Gene and Ben 1992 SVX LS AWD 110K - Liquid Silver 1994 SVX LSi AWD 128K - White Pearl (daily driver) 1994 SVX LSi AWD 95K - Emerald Pearl (sold) 1992 SVX LS-L AWD 115K - Dark Teal 4.44 swap (sold) |
#13
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Re: Growling and humming from the rear
The sway bar bushings shouldn't be a big deal. Be sure they're not cracked. Oil-soaked front bushings should be replaced. Seems more likely that a rattle from a sway bar would be due to bearing deterioration. I know from experience that having one split apart and fall out results in an awful racket.
dcb |
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