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Growling/Clunking noise in rear while accelerating hard in 1st or 2nd ??


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My guess is also rear diff. I used to occasionally happen in my '02 RS under hard acceleration while turning in very cold weather. Sounds identical in my LGT as it did in the RS.

 

I think it also goes away after the car warms up, so I'm guessing just the diff not reacting as well while the fluids are all still a little cold.

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No... this is different. Straight line not turning. And it doesn't do it when the temperature gets above ~55 deg F.

 

It doesn't matter if the car is cold or warmed up, either.

 

I know ... I'm saying I get that sound in my car now (current temp at lunch: 17*) and I used to get the same sound in my RS when it was still colder (below 0*) while in turns. Same sound, same weather conditions, only difference was I needed a turn in the RS to make the diff "work"

 

I know which sound you're talking about ... been getting it the last couple days with this weather, and I'm saying I got the same sound under similar but slightly different conditions in my RS.

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No... this is different. Straight line not turning. And it doesn't do it when the temperature gets above ~55 deg F.

 

It doesn't matter if the car is cold or warmed up, either.

 

 

the diff doesnt just work when you are turning. if you accel hard, the diff will tr to preven the one whell with the least amont of traction from spinning out of control as it would in a non-limied slip diff. the sound is could be the clutches slipping allittle and heating up while transfering power. it also could be the whole diff housing twisting under power, ot maybe the rear u-join on the drive shaft twisting. we know its happening under power only so its not the suspension. its somewhere in the rear of the drivetrain.

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I know ... I'm saying I get that sound in my car now (current temp at lunch: 17*) and I used to get the same sound in my RS when it was still colder (below 0*) while in turns. Same sound, same weather conditions, only difference was I needed a turn in the RS to make the diff "work"

 

I know which sound you're talking about ... been getting it the last couple days with this weather, and I'm saying I got the same sound under similar but slightly different conditions in my RS.

 

Oh... I understand.... sorry. :wub:

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the diff doesnt just work when you are turning. if you accel hard, the diff will tr to preven the one whell with the least amont of traction from spinning out of control as it would in a non-limied slip diff. the sound is could be the clutches slipping allittle and heating up while transfering power. it also could be the whole diff housing twisting under power, ot maybe the rear u-join on the drive shaft twisting. we know its happening under power only so its not the suspension. its somewhere in the rear of the drivetrain.

 

 

Yeah.. I hear ya. Mine doesn't make any noise at any other time, however... even when turning. Only at higher RPM under load.

 

I would guess that you are right with the thought of it being the diff housing rolling upward... Maybe it's hitting the pinion nose snubber or bumpstops.. and tranfering noise/vibration into the cabin through the floor.

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  • 3 weeks later...

On more investigation I find it is a lot easier to induce the noise on an accelerating right turn vs accelerating left.

 

If our engines spin the same way most RWDs do (spins rr tire because it tries to lift it) then this has to be coming from something in the rear sub-frame, diff, or rear drivetrain.

 

I thought it may be from the center bearing, but I don't think what I have recently found supports that theory.

 

Also, it sounds like it is coming from the rear.

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Mine does it in a straight line... not while turning, Blue.... at 40MPH at 5000 RPM. The tires aren't spinning.

 

IMHO, It is a harmoic vibration that is coming through the floorboard... either a bushing that is less pliable at colder temperatures... or a rub. I am not sure which. My money is on stiff rubber bushings. The vibration of the drivetrain is getting passed right into the cabin due the the bushings being cold and stiff.

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Mine does it in a straight line... not while turning, Blue.... at 40MPH at 5000 RPM. The tires aren't spinning.

 

IMHO, It is a harmoic vibration that is coming through the floorboard... either a bushing that is less pliable at colder temperatures... or a rub. I am not sure which. My money is on stiff rubber bushings. The vibration of the drivetrain is getting passed right into the cabin due the the bushings being cold and stiff.

 

Mine does it in a straight line too, and I think you are right about the rubber bushings.

 

Try accelerating hard enough to make the noise, while exiting a right turn: I bet it will be worse. Then try the same thing in a left turn, I bet it will be a bit better.

 

Now you get what I am saying?

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Hmmmmmmmmmm... I haven't tried that actually. Full throttle left and right turns aren't exactly safe to do going to/from work. :lol:

 

If I get a chance and some open space, I'll try it.

 

It is cold here (not crazy cold, but cold enough for the noise) but it is dry. I can easily make the noise on a half throttle right turn at 4500 rpms.

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On more investigation I find it is a lot easier to induce the noise on an accelerating right turn vs accelerating left.

 

If our engines spin the same way most RWDs do (spins rr tire because it tries to lift it) then this has to be coming from something in the rear sub-frame, diff, or rear drivetrain.

 

I thought it may be from the center bearing, but I don't think what I have recently found supports that theory.

 

Also, it sounds like it is coming from the rear.

 

I notice the same too. I'm just glad that more and more people are coming out on this. I thought my car was F$ckd when I was the only one getting it.

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I just started to get this at 26k miles. Didn't here this last winter on stock prings, I am now on H-tech springs and started hearing this recently.

 

It seems to happen on stock cars too, but requires even more aggressive acceleration/colder temps to notice it.

 

Lowering the car seems to cause the noise to happen easier.

 

Obviously it is not the fault of the springs, they just magnify an already existing problem.

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  • 3 weeks later...
Mine does it in a straight line... not while turning, Blue.... at 40MPH at 5000 RPM. The tires aren't spinning.

 

IMHO, It is a harmoic vibration that is coming through the floorboard... either a bushing that is less pliable at colder temperatures... or a rub. I am not sure which. My money is on stiff rubber bushings. The vibration of the drivetrain is getting passed right into the cabin due the the bushings being cold and stiff.

 

 

Anyone try the Whiteline Rear Differential Bushing Kit? I just went to stage 2 from TDC Stage 1 this past weekend and the vibration during accelleration is alot worse now:(

 

wonder how hard this is to install? Can't be too bad.

http://www.kastleskorner.com/product_info.php?cPath=77_257_263&products_id=782

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Lachute performance had a customer change his whole LGT back to stock, then take it to the dealer to find the problem.

 

Long story short they changed almost everything back there, axles, rear diff, etc... and it still makes the noise!

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wow...not what I wanted to hear! so how did the dealer it off? are they going to contact SOA?

 

 

Not sure of the first question.

 

They got SOC (Subaru of Canada) involved. I will notify this forum as soon as I know of any possible solution to this problem.

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