Weird Sounds from a 98GT

N

north

New member
Background on the car, '98 Legacy GT, 175k body, 115k motor(new timing belt, head gasket etc...). As far as I know nothing has been replaced suspension or drivetrain wise.

Question #1

So the first sound is coming from the front of the car, it almost sounds like a loose belt. However, if I depress the clutch slightly, the sound goes away. Vice-versa when I let off the clutch, the loose belt sound returns. Any ideas?

Question #2

Noticed today a loud noise coming from the rear of the car, high pitched almost squealing so I crawled under the back. The rear diff cover is caked with oil and road crap, and the sounds seem to be emanating from there. Do I need to replace the diff? If so, can I use the diff from a WRX? Also what years work (I assumed 02-03?).

 
1# sounds like the throwout bearing squeaking. trans will have to come out to replace.

2# its possible, but could also be a break issue. gear ratio is 4.11 for 5mt and 4.44 for 4eat. a automatic wrx rear diff will work if your car is 5mt, but other then that id just replace with the regular legacy diff.

 
It is a 5MT, will a WRX 5MT work? I saw one for sale on here. Wouldn't the throwout bearing be the opposite, and squeek when the clutch was pressed down rather than when it was released?

 
Great. Sucks because it had a new clutch installed 1k miles ago. Any info on the noise from the rear diff area?

 
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No, yo can't use a 5mt wrx diff. They're 3.54, or something stupid like that.

When my diff failed it started just whining on deceleration while in drive (same as being in gear for you). It got really bad after a while so I replaced it. Noise went away.

Diffs don't fail hugely often though, I'd check bearings and brakes first.

Was the throw out bearing replaced when the clutch was replaced?

If it wasn't, what idiot installed the clutch?

 
No idea. Got the car from a family friend that owns a dealership. I have been hearing a whining noise during decel from the front, but not the rear (I don't think). The noises from the rear are while the vehicle is NOT in motion, that is why I am ruling out brakes/bearings. No idea if the throwout bearing was replaced. Does any of this info help at all?

 
If the car is not moving then the rear diff can not make noise. The only thing back there to make noise to my knowledge is the fuel pump. I can faintly here mine.

 
The fuel pump is in the tank, submerged in fuel. The one in my 98LGT is barely audible. When you turn the key from off to RUN (not start) the fuel pump will run for about two seconds and shut off. Only if I listen really closely will I hear a faint whirr from mine, it's more the sound of moving fuel than anything.

With the engine running I can hear it if I put my head on the seat and really listen. But if it makes the noise when you first turn the key to run, it's the pump. Otherwise, it's not the pump.

When you're stopped, does the noise change, or go away when you push the clutch?

The farthest thing back in the driveline that moves when the car isn't moving is the transmission input shaft. The back bearing does fail on those, so if you push the clutch and it changes, it could be that.

Also, a leak in the exhaust can make a hisss noise. You can exaggerate it by blocking the end of the muffler with a rag.

Whirring from the front is usually wheel bearings. Check them.

 
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Alright lets tackle these questions. It is not the fuel pump, I do know what those sound like it isn't a faint sound and is constant regardless of how long the car is running. I haven't checked to see if playing with the clutch changes the rear sound. Doesn't sound like exhaust, when I place my head under the rear of the car, it literally sounds like the sound is coming from the diff cover area, and sometimes it rattles. I haven't put it up on jacks yet to find out exactly where the sound was coming from. The whirring from the front only occurs on decel, almost like the gearbox noise you hear in the highend rally cars? I'm not into to rally yet, so I can't think of what the sound is haha. I may just try to record a video on my phone of the sound to make it easier.

 
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Does it do the whirring noise when not in gear? Does it change when you turn left or right? That'll help rule out wheel bearing.

It sounds like you're describing front diff noise, or bearing noise in the tranny. Hopefully it isn't that. Have you checked the transmission oil level and color?

I had one that leaked. It would start whining when it got low, and stopped when I topped it up.

The rattle is probably something loose. First thing that comes to mind is exhaust heat shield. But that's on the header back to the cat. So you wouldn't hear it at the back of the car. I'd put the car on stands (don't get under it supported by a jack). Take a pry bar or something and start poking and banging on stuff. When you hit whatever is rattling, it'll stop. Then you'll know what it is. I think heat shield up at the front, sometimes it's hard to know where rattling sounds are coming from.

 
My thought was heat shield, but there aren't any in that location. My mother used to have an outback that almost every heatshield on that car came loose haha. The whirring noise from front I have not checked while rolling at neutral, but that wouldn't cause decel really. I will check it tonight. It does not matter if I am going straight or turning, that's why I ruled out bearings. I will definitely check transmission level tonight as well. I'm off for my motorcycle road test today so the legacy has to wait. An no, I would never go under a car supported by jacks alone...that's asking for issues.

 
Alright so it DOES do it even with the clutch depressed. I guess the best way to describe the sound would be to say it almost sounds like straight cut gears in terms of the type of sound, it is nowhere near as loud, but hopefully that gets the sound across. Have not checked transmission level yet, a lot going on with finals etc...

 
north said:
Alright so it DOES do it even with the clutch depressed. I guess the best way to describe the sound would be to say it almost sounds like straight cut gears in terms of the type of sound, it is nowhere near as loud, but hopefully that gets the sound across. Have not checked transmission level yet, a lot going on with finals etc...
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Well, with the clutch in, it's not inside the transmission. Nothing in the transmission is turning when you push the clutch.

So it's either throw out bearing or pilot bearing.

OR a whining sound could be power steering, or alt/ac bearings.

It's something forward of the transmission though if you get it with the clutch in.

All else it could be is a weird high pitched exhaust leak farther back, but it sounds like that's not the problem.

Does it change or go away if you rev the engine with the clutch in?

 
I'll check that out tomorrow
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I DO know that the throw out bearing is bad. Also, the clutch engages almost at the TOP of the pedal travel, is this normal? I was informed it was a new clutch with approx 1000 miles per the dealer. Does a bad diff sound like the sound I described?

 
Bad diff is a whine. A friggin' annoying one at that. But if you're not moving, it's not a diff.

Clutch should engage somewhere in the middle, it could be a poorly bled hydro clutch. Your should be hydro.

I'm better at making cable setups work properly. If the TOB is bad, it's probably the TOB making noise. Replace it. Not much else will make a horrible bearing noise with the clutch is. If the TOB wasn't replaced, I suspect the pilot bearing wasn't either. And they probably didn't grease the pivot ball.

Take it apart and do it correctly. You've learned a valuable lesson that if you don't do something right the first time, you have to do it again. Feel lucky you weren't the one who screwed it up in the first place, that makes you even more mad ....

I'd rather be mad at someone who used to own the car than myself.

 
My reason for asking about the diff is because it ONLY happens while moving (the PPG type noise). And only while decelerating (that I can tell). Would this still be TOB/ Pivot Bearing? What is the best way to bleed a subaru clutch, and by that I mean, where should I bleed it from?

 
There's a bleeder on the slave cylinder. It's a pain in the butt.

Oh, I thought you were saying this noise was ALL the time. Only on decel sounds damn like a diff to me, having just gone through that. And now my replacement is making noise
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I'd check the wheel bearings first, but try to change the rear diff oil. Then you'll get to see the colour, smell, and how much crap is on the magnet. If there's a formidable mountain on the magnetic plug, it may be past it's prime.

 
Yeah just to clear it up, the noise I hear ALL THE TIME is from the REAR of the car, around the diff area (not loud enough to be noticed during driving conditions). The noise I hear DURING DECEL is from the front, and sounds like the straight cut gears.

 
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