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Help? Rumbling vibration from rear wheels on accelleration from start. Any ideas guys

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Help? Rumbling vibration from rear wheels on accelleration from start. Any ideas guys

 
Old 10-08-2007, 05:18 PM
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Shemmer
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Default Help? Rumbling vibration from rear wheels on accelleration from start. Any ideas guys

I am noticing a strange vibration coming from the rear of the car when I start making a corner from a complete stop. The feeling is almost as if one of the tires is completely flat. It ssems to happen regardless which way I turn and rumbles throughout most of the turn. It doesn't happen while in motion or from a rolling start, only from a complete stop when making a turn.
Where should I look?

(BTW 1981 930)
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Old 10-08-2007, 05:59 PM
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nathanUK '81 930 G50
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Do you have a LSD?
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Old 10-08-2007, 07:03 PM
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I've had noises like this in the past, one was a wheel bearings, the other was actually the emergency brake pads needing replacement as they were cracked and falling apart. If you disconnect the cv and isolate the wheel turn it by hand, might give you a better idea of where it's originating.
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Old 10-08-2007, 07:41 PM
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Originally Posted by nathanUK '81 930 G50 View Post
Do you have a LSD?
Yes, limited slip diff.
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Old 10-08-2007, 07:44 PM
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Originally Posted by slivan View Post
I've had noises like this in the past, one was a wheel bearings, the other was actually the emergency brake pads needing replacement as they were cracked and falling apart. If you disconnect the cv and isolate the wheel turn it by hand, might give you a better idea of where it's originating.
I had my mechanic tell me that my drivers side wheel bearing was noisy but I don't think it can make my whole car shake that bad. He also quoted $700 for one side. Is that normal? Seems a little over the top to me.
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Old 10-08-2007, 09:16 PM
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If you have a LSD and no slip oil in there like Redline gearbox oil with the NS at the end it will chatter just like you describe as the LSD clutches grip then slip and grip then slip repetitively making low frequency vibrations as you describe accelerating slowly around corners. Especially 90 degree corners at intersections.
That type of oil may be better for racing because it will lock up the clutches better under high torque accelerations but on the street during slow accelerations it can be annoying.
Change the transaxle oil to the type that doesn't have the no slip aditives and if thats what it is it will stop it.
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Old 10-08-2007, 09:27 PM
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The description you've posted sounds very accurate. I( will have to ask my mechanic what oil is in there and possibly take the steps you've described. Will there be any harm in putting an oil in without no slip additives?
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Old 10-08-2007, 10:33 PM
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You can't really tell what kind of oil is in there by looking at it unless it is the only blue or green oil made.
Lots of people like the swepco best so I'm sure it's good.
Mobil GL5 synthetic SHC 75w-90 is excellent.
I'm sure Amsoil, Redline, and Royal Purple 75w-90 GL-5 synthetics are excellent too.
You can usually buy them by the gallon too. Makes it easier to fill and is sometimes cheaper.

Just don't get the non slip stuff because you want the clutches to slip smoothly when turning and accelerating gently during street driving if you don't like the chattering.
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Old 10-09-2007, 12:00 AM
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If it turns out to be a wheel bearing, do it your self. $700 for one wheel sounds really high to me. At $90 per hour for labor plus the bearings that still comes out high.
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Old 10-09-2007, 01:24 AM
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I had some vibration and noise (clunking) when I snapped a few of the bolts that hold the 1/2 shaft. The looked like they were ok, they were still in the hole, but were snapped inside. You couldn't tell until you spun them by hand. Just a thought.
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Old 10-09-2007, 05:07 PM
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nathanUK '81 930 G50
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As you have a LSD that noise is normal.
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Old 10-09-2007, 06:21 PM
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Shemmer, are you selling your car?

http://cgi.ebay.ca/ws/eBayISAPI.dll?...ksid=p3907.m29
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Old 10-09-2007, 09:39 PM
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Originally Posted by slivan View Post

I can't believe my freekin eyes!
About 2 years ago when I bought my car I started searching for a pic to use as my avatar because I didn't have any of mine when I came across this shot which looks identical to mine, even the rims. Well last night I'm browsing ebay and I see the same picture that I'm using and say to myself, "what are the odds?" Not only is this guy selling the car but he's in Toronto also. OMG

Last edited by Shemmer; 05-02-2009 at 11:04 PM.
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Old 10-09-2007, 09:44 PM
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OK Shemmer...

Come clean with us. You're a troll looking to get your jollies by asking us stupid question that you know we will answer because we are good guys and think you are one of us. BUT you've been had!



Just kidding!
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Old 10-10-2007, 12:23 AM
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Wow! Thats some coincidence!!!!!!!
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