2000 Legacy Grinding / Rubbing Noise - Clutch Issue or Engine Rebuild Time?

[dirty_mech]

Hi guys.  This is my 2000 Legacy Wagon L M/T at 235K.   

A grinding / rubbing / scraping noise has started coming from my engine.  It is most noticeable when first starting the car and running at idle, although it can still be noticed when running the car.  Here are 3 behaviors that will probably allow someone to name the issue:

- Pressing the clutch pedal to the floor makes the sound disappear completely.
- Revving the engine with the pedal to the floor causes no sounds.
- Revving the engine in neutral without pressing on the clutch pedal not only causes the noise, but the noise increases in frequency and pitch along with engine speed.

Is this most likely some kind of clutch issue with the clutch plate, the pressure plate, or the release bearing?  Or could it be engine damage?

I'm asking because I discovered my engine oil was very low when the noise first started.  Forgot to add Lucas oil stabilizer last oil change so it was eating oil much faster than I anticipated.  I was so certain the noise was engine damage that I bought a new 2013 Outback.  However I've been driving it for over 3 weeks without performance issues, so I'm starting to suspect this is a smaller problem than I originally suspected, such as an annoying clutch noise.  I was overdue for an upgrade anyways so I'm not upset if this turns out to be a just clutch issue.

I did the clutch 18 months ago.  I used an Exedy 15801 Stage 1 racing clutch kit which has been performing excellent so far.  However I did afterwards notice a weird mechanical sound bouncing off the freeway divider when I'm driving fast, which gave my car an almost diesel-engine sound.  It was concerning at first but subsided with time and I haven't noticed it for quite a while.  So perhaps I did something wrong during the clutch job and it's only started to become an issue now.

So what do you guys think?  Is this a bad clutch component?

I suppose it could be a transmission or engine issue, but both have been performing perfectly.  The only problem is this noise. 

Edit:  Here's a video so you can hear and see how the noise behaves relative to engine speed and clutch pedal position.

https://imgur.com/tdu5fe2

Edited September 27, 2022 by dirty_mech

[heartless]

1 hour ago, dirty_mech said:

- Pressing the clutch pedal to the floor makes the sound disappear completely.
- Revving the engine with the pedal to the floor causes no sounds.

based on these statements, i would say definitely clutch related.

[dirty_mech]

4 hours ago, heartless said:

based on these statements, i would say definitely clutch related.

Yeah I think you're right.  Now the question is which part.

Is it possible this is just the release bearing causing the noise?  Because I already have a spare release bearing ready to go.  I reused the old release bearing because (1) it only had 18 months on it to begin with, and (2) it was an oversized bearing that worked in conjunction with a quill repair sleeve. 

Perhaps the bearing and/or quill repair sleeve have gone bad and I can get away with just swapping out the bearing?

I guess I would need to know what is the most likely component to cause all this noise.  I'd like to avoid replacing the whole clutch kit over a glorified squeak.

Edit:  Based on this video, I think it is the throwout bearing:

I think I'm going to try and just replace the bearing.  What a pain...

Edited September 28, 2022 by dirty_mech

[heartless]

at 235K i would think it is due for a complete refresh...

why screw around with doing just one thing?

If you have to take things apart, do it all, and be done with it for a while.

[el_freddo]

It’ll be a clutch throw out bearing - the symptoms you shared are text book TOB wearing out.

Cheers 

Bennie

[moosens]

That 18 month old TO bearing , was that Genuine Subaru or an aftermarket? 
 

 

[Numbchux]

Could be throwout, but also absolutely could be internal to the transmission. I would get the car up in the air, running in neutral and poke around with a stethoscope. See if the noise is coming from in the bellhousing (listen right on the clutch fork), or from the case itself.

Change the fluid and see what the drain plug looks like.

[1 Lucky Texan]

wait, NO noise when clutch disengaged?

 

kinda points to trans input shaft bearing doesn't it?

 

is it noisy in Neutral, foot off the clutch?

 

I have read once of a clutch spring that got loose inside the housing....made a lot of racket.

[dirty_mech]

On 9/29/2022 at 7:27 AM, 1 Lucky Texan said:

wait, NO noise when clutch disengaged?

kinda points to trans input shaft bearing doesn't it?

is it noisy in Neutral, foot off the clutch?

Yes it is noisy in neutral with the foot off the clutch.  I think you might be onto something Texan.  Please help me out here.

I just replaced the clutch release bearing and the noise is still present.  Very unsatisfactory result but I was able to reboot the blown CV axle boots while I was at it, so not a total loss.  Put some photos below.

It appears the issues now must be my transmission.  I'm very nervous about this because I know diddly-squat about transmissions, even the manual ones.  I suppose I could try to hunt one down but this one seems to be working great except for the grinding noise.  I would rather fix it if possible. 

An issue I noticed when the transmission was dropped was that while I turned the input shaft by hand while the axles and shaft were all uninstalled, there was a click-click-click noise.  Some sort of unevenness in the rotation.  This and the not-terrible condition of the old release bearing made me very nervous the transmission is having an issue.

Is this likely to be the input shaft bearing? Because the transmission works fine other than for this disturbing faint grinding noise. Is this something I could perhaps fix at home or no? Looks like the input shaft bearing is around $40 from the dealer, but the schematic makes it look quite complicated (see photos below).

I've got a lot of experience but this might test me.  Let me know what you guys think.

Edited October 4, 2022 by dirty_mech

[dirty_mech]

So I just watched a video video on replacing the input shaft bearing on a 2012 Subaru 5-speed transmission.  Link at the bottom since I can't resize the embed.  Not the right year but looks similar enough to give me an idea.  In the video, the gentleman points out 2 different bearings on the input shaft that could go bad.  So perhaps I will need to replace the larger rear bearing?  I'm not even sure what is the part name of the second bearing.  It also shows a paper gasket at one point that needs to be scraped and replaced.  Might be RTV on my model but I'll have to figure that out as well.

Here's a photo with the positions of the 2 bearings.  I think the front input shaft bearing is the one on the left, but he says the larger one in the back went out on him before in the original transmission:

Starting to look a bit involved, but I'm not discouraged yet!  What do you guys think, can I do it?

 

Edited October 4, 2022 by dirty_mech

[dirty_mech]

So I watched the full 3-part series on this guy's Subaru transmission repair.  I am confident that I could do the repair, but I wondering if it's more effort than just snagging a transmission from Pick n Pull, if possible, where they will only charge me about $200 if I pull it myself.  I might try doing that, but it would be cool to fix the transmission on my own.  Would love to hear your guys' opinions on what route I should take.

The third part of his project (embedded below) shows that the input shaft made a click-click-click noise just like my input shaft, and that the noise was gone once he replaced a couple bearings and put it all back together.  The video series has encouraged me to try and fix this myself.  The only issue is I will need to disassemble the transmission and inspect the input shaft before figuring out which bearings have gone bad.  Apparently there are several that can go bad, one for each of the gear sets, and not just the front bearing. 

In his pre-video on replacing the center differential, he mentioned that the 75W-90 gear oil these transmissions call for should NOT contain limited slip additive.  Or at least on his 2012 transmission.  Are you guys familiar on whether this also applies to the transmissions from 2000?  I wasn't paying attention to such a requirement and may have used an oil with that additive on my last gear oil change.  Is that something that could've caused this problem or a different problem?  I also added Lucas Oil Stabilizer to the gear oil in my transmission and rear diff.  Any opinions on whether that also could've potentially caused damage?  I'm a bit keener on following OEM specs to the letter these days, so will plan to use what is strictly specified next time.

Edit:  Just wanted to say that I absolutely swear by putting Lucas Oil in the engine during oil changes.  Only because my engine is so old and eats so much oil otherwise.  My 235k, EJ251 engine will eat oil about 4x as fast without Lucas Oil, requiring half a quart or more every other fill-up, and that's when I'm using Mobil 1 High Mileage 10W-40.  I would've probably had to rebuild my engine at this point without that stuff.  Don't know if it's a problem in the transmission and rear diff however.  I was so impressed by how it helped my engine that I didn't even think about it when putting it in my powertrain devices.  Perhaps it could be a problem by increased viscosity allowing debris in the bottom of the case to be more easily picked up and run through the components during operation?

 

Edited October 4, 2022 by dirty_mech

[1 Lucky Texan]

I have zero experience wrenching that deep. I suppose, changing both bearings, maybe inspecting some other stuff, could be a good idea.

Or, check car-part.com for a used trans. Might even find one with a lot fewer miles than yours.

 

I'm sure others here could guide you if you proceed.

[el_freddo]

Gearbox work is always fun - you’re only looking at replacing bearings which oddly is something I haven’t done on the upper and lower gear set shafts. I’ve only done bearings on the input (dual range), rear output and centre diff bearings. They’re easy to get to. 

The front bearing should be relatively easy, that rear bearing will require a press no doubt. It’ll be easy to identify the offending bearing by spinning it  

You should also read up on the torque specs for that upper gear set shaft so you know what you’re up for. Check out their special tools to hold the gears without damaging them, make them up to do the job. 

At the end of the day you could have your cake and eat it too. Setup for the gearbox repair work but go get a replacement gearbox to swap in while you play doctor on your current box. 

Ditch the paper gasket and use the same goo that you seal the front cases with. You only need a tiny smear of that stuff for it to do it’s job! 

The hardest part of this job to me is setting the diff properly. I’d recommend marking the sun dials, back them off two or three times, write down how many turns out you did in relation to your two marks, this allows the front cases to boot and torque down properly without having the diff fight the cases. 

If you’re going to replace the diff bearings throw the above out the window as you’ll need to set the backlash (from memory that’s the correct term, the other one is preload) anyway and that’s a whole other procedure to follow. I’ve back yarded mine and done it by feel, no problems (yet??). 

Also a good time to replace all the seals - input, front diff, O ring on the sun dials, rear output shaft and the selector shaft seals. 

It’s really interesting and satisfying pulling down a gearbox, fixing stuff and managing to put it all back together again - then be hyper vigilant with every little noise you hear once it’s back in the vehicle! 

Some tips: 
- get a copy of the WSM for your model, read up on what you’ll be doing, find the torque specs and bolt torque sequence diagrams
- use a cardboard panel to draw the gearbox outline on with all the bolt holes, number them in the torque sequence order (remove starting with last bolt number!) and place the respective bolt in the same location on the diagram (take note of which side of the gearbox the bolts come in from, I can’t remember which side without having a look) 
- write out the different torque specs for the various bolts. This saves time once you’re in the thick of it! There are two different toque specs for different bolts on the front cases, the bolts around the diff have a higher torque than the others 
- take photos as you go so you have a reference to fall back on if needed 
- have some blocks of wood to help sit the box on its side so it won’t wobble around on the floor/bench (I highly recommend doing this work on a bench!)
- ensure all mating surfaces are cleaned properly before sealing the cases and rear housing. Use a residue free solvent as the final wipe down before applying the silicone 
- have those torque specs handy for the sealing of the front cases, also have the two socket sizes ready to go 
- it’s a good time to throw a front LSD in, just saying!! (Worth the effort in my book) 

That turned out to be essay spec, I hope it’s given you some idea of what’s involved.

Cheers 

Bennie

[Numbchux]

No small project to split the cases and replace the bearings, and there's a lot of "while your in there" things to consider on a 235k mile trans. I've had many manuals apart, and put a couple back together and used them. I would definitely not bother, not with how easily a good used transmission can be sourced.

[dirty_mech]

Hi guys.

Thanks for getting back to me Lucky Texan.  Me neither! 😅
I'm always game to learn more about fixing these cars if necessary, but I'm getting to an age where I'm trying to avoid it.

THANK YOU el_freddo for the very detailed guide on how to do this.  That is excellent information.  Even if I don't repair the transmission, that is an info will be helpful to anyone who might run into the same problem.  I'll definitely be using it if I ever have to repair one of these transmissions. 

Hi Numbchux.  Yeah, that's what I figured.  I'm not even sure I want to go as far as replacing the transmission because I plan to sell this car.  Not sure it's worth the time to fix. 

I'm going to start a new thread on this issue because I have some specific questions regarding my situation, now that I know the transmission is the issue.  Thank you guys again.