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2001, Subaru, 2.5RS, BRP
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Discussion Starter #1
2001 2.5rs, 5-speed, 2dr. Recently I've been hearing a popping sound from the rear of my car when I'm driving at low speeds or when I go over a bump. I don't think it's the exhaust problem 98-01 2.5rs's are know about. It seem the sound is coming from the rear differential or something? I remember reading that with impreza's sounds of this sort are normal because it's AWD. But my problem is it's happening a lot lately. My car is still under the powertrain warrenty (it has 18,000 Miles). Any help would be great.
Thanks in advance,
Poopysnaps
 

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jack up the rear end and spin both wheels. if you get alot of resistance (esp from one), then it might be time for a new diff. of course, even if it seems fine, it could still be on the outs. the only way to know for sure is to take it off and open it up.
 

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ok, since I have actually blown my rear diff (MY 99 open diff) listen close...this is what I learned/experienced.

Is the sound audible only when decelerating or cruising with NO throttle?

Can you "feel" the noise vaguely in your shifter?

Does it go away when applying an engine load, or corniering?

Have you been rallycrossing or autocrossing HARD for a while?

Like 10th said (he helped swap out my last one)..jack up the rear of the car, spin one wheel, the other should go the opposite way. The, have someone else HOLD the other wheel still, and feel the play in the diff, if it makes your popping sound as you do this, take it to a shop to check it out.

You can also drain and refill your diff, check for large amounts of metal chunks or particles on the magnetic drain plug...usually a sign of a failing diff. Some fine (poweder like) metal is to be expected, look for bigger bits.

I blew 12 teeth off my rear diff, and managed to wedge a tooth between the ring and the carrier....its a bad sound and expensive if you thrash it. Although swapping it out isnt too hard if you have 3 people, airtools and jack stands.

Good luck, I hope its not your diff.
 

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STiShawn said:

Like 10th said (he helped swap out my last one)..jack up the rear of the car, spin one wheel, the other should go the opposite way.
I thought that was only for open differentials? Doesn't he have a LSD?
 

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Discussion Starter #5
ok, since I have actually blown my rear diff (MY 99 open diff) listen close...this is what I learned/experienced.

Is the sound audible only when decelerating or cruising with NO throttle?

The sound is present when I'm decelerating at low speeds, when cruising at low speeds and during acceleration.

Can you "feel" the noise vaguely in your shifter?

I'm not completely sure about this one but, I feel the "popping" through out the who car for sure. I get the sound epscially when I go over speed bumps.

Does it go away when applying an engine load, or corniering?

The sound goes away at high speeds,

Have you been rallycrossing or autocrossing HARD for a while?

The car has never been raced

Thanks for all your help =)
.
 

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Just a thought. Broken rear strut? From what you said about the speedbump thing.
 

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yeah also check your strut mounts...see if one of the three bolts broke off...or if the center bolt from the strut isn't attached to the strut mount...mine was loose once, and made a noise like that.
 

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hrmm....odd. You sure its from your rear diff?
I agree with the check your rear suspension, is it stock or have you installed an aftermarket kit? I know I had to re-torque my rear strut tops down after a week.
Good luck, you can do what I did...drive it till it breaks.... then at least you'll know whats wrong....
 
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