Drivetrain rattle driving me nuts

[Bariki]

Ever since I got my clutch replaced years ago, my 2004 Legacy B4 has made a kind of a rattling sound that seems to be coming from somewhere below the shifter.

It occurs at low speeds when I start the car (especially right as the clutch pedal pressure is released), but it also happens at high speeds (65+ mph). However, it might actually be at least two different rattles.

What could it be?

I've replaced the suspension, front half shafts, a control arm, and front wheel bearing for various reasons and nothing seems to make a difference.

 

I suspect maybe it's a bad transmission mount or the propeller shaft.

 

The front differential also seems to have quite a bit of backlash, but I don't know how much is normal.

Edited June 13, 2023 by Bariki

[Bariki]

The center bearing of the drive shaft wasn’t bolted down properly…

[m sprank]

It took years for you to decide to hunt that down?  Then you came to the forum without actually checking the most basic of process/procedure from the work that was performed immediately prior to the noise occurring.  When no one answered you finally decided to look for real.  Man this place is comedy. 

[Bariki]

8 hours ago, m sprank said:

It took years for you to decide to hunt that down?  Then you came to the forum without actually checking the most basic of process/procedure from the work that was performed immediately prior to the noise occurring.  When no one answered you finally decided to look for real.  Man this place is comedy. 

I had multiple mechanics who were unable (or unwilling) to diagnose it, so I just lived with it, because I assumed the repair would be expensive. It hadn't occurred to me that it could be something so simple. Plus, I wasn't even sure where it was coming from, so I didn't know where to look until I had eliminated all other possibilities. No need to be rude.

[m sprank]

5 hours ago, Bariki said:

I had multiple mechanics who did not know their ass from a hole in the wall, so I just lived with it, because I assumed the repair would be more painful than prison anal sex. It hadn't occurred to me that it could be something so simple. so I didn't know where to look until I had tickled all the other extremities. I drink Bud Light exclusively.

THANK YOU to all who contributed to leaving my cooler with over 70 different local micro-brews.  Over 2 liters later... Please try the veal, I will be here all week.

 

@Enlight @BoozeRS05
@boxkita @KZJonny
@tysparks81

@silverton
@JJBerk
@SubOperator
@jaylew
@thefultonhow
@Chronuss
@Infosecdad
@JmP6889928

Edited June 20, 2023 by m sprank

[Bariki]

Maybe try being useful instead of being funny?

[Infosecdad]

On 6/17/2023 at 1:11 AM, Bariki said:

The center bearing of the drive shaft wasn’t bolted down properly…

Thanks for coming back to let us know what the root cause was, not everyone does that.

 

11 hours ago, Bariki said:

I had multiple mechanics who were unable (or unwilling) to diagnose it, so I just lived with it, because I assumed the repair would be expensive. It hadn't occurred to me that it could be something so simple. Plus, I wasn't even sure where it was coming from, so I didn't know where to look until I had eliminated all other possibilities. No need to be rude.

I get this, you trusted the mechanic because they are supposed to know better.  Unfortunately, as you found out, many of them are seriously winging it and don't know what they are doing. This is why I've gotten into doing all the work on my car, too many times they couldn't cover the basics.  

[Bariki]

28 minutes ago, Infosecdad said:

Thanks for coming back to let us know what the root cause was, not everyone does that.

 

I get this, you trusted the mechanic because they are supposed to know better.  Unfortunately, as you found out, many of them are seriously winging it and don't know what they are doing. This is why I've gotten into doing all the work on my car, too many times they couldn't cover the basics.  

Yeah, the only reason I even mentioned the cause was in case it would help someone else with a similar problem down the road.

I’m not sure if a clutch job even involves removing the center bearing, but logically this is the most likely reason.

Now I just have to fix one dragging caliper and I’ll be golden…

 

[thefultonhow]

6 hours ago, Bariki said:

Maybe try being useful instead of being funny?

I think what he was saying is, he was drunk AF when he wrote that.

[silverton]

7 hours ago, m sprank said:

THANK YOU to all who contributed to leaving my cooler with over 70 different local micro-brews.  Over 2 liters later... Please try the veal, I will be here all week.

 

@Enlight @BoozeRS05
@boxkita @KZJonny
@tysparks81

@silverton
@JJBerk
@SubOperator
@jaylew
@thefultonhow
@Chronuss
@Infosecdad
@JmP6889928

Thanks for the shout out buddy but I wasn't there does sound like it was a good time though!

59 minutes ago, Infosecdad said:

Thanks for coming back to let us know what the root cause was, not everyone does that.

 

I get this, you trusted the mechanic because they are supposed to know better.  Unfortunately, as you found out, many of them are seriously winging it and don't know what they are doing. This is why I've gotten into doing all the work on my car, too many times they couldn't cover the basics.  

This is so true, I say this as one of those 'trusted mechanics'

26 minutes ago, Bariki said:

Yeah, the only reason I even mentioned the cause was in case it would help someone else with a similar problem down the road.

I’m not sure if a clutch job even involves removing the center bearing, but logically this is the most likely reason.

Now I just have to fix one dragging caliper and I’ll be golden…

 

the center bearing is a unit with the driveshaft, it definitely comes out.

[boxkita]

@silverton

planning for next year has started

https://www.legacygt.com/topic/139243-ecm-2024-planning-thread/?do=getNewComment

[Bariki]

43 minutes ago, silverton said:

Thanks for the shout out buddy but I wasn't there does sound like it was a good time though!

This is so true, I say this as one of those 'trusted mechanics'

the center bearing is a unit with the driveshaft, it definitely comes out.

Right, come to think of it, it would be a huge pain in the ass to pull or reinstall the transmission with the driveshaft in the way... I was thinking maybe it had been thrown out of balance, but thankfully it was something much simpler.

[silverton]

You're kinda correct though, with the carrier bearing housing not being bolted down properly, it was out of balance.

[m sprank]

Anyone who missed correctly installing the drive shaft carrier bearing after removal for a clutch job should not be performing clutch jobs professionally. 

Only way the driveshaft stayed in position is if they removed the engine to replace the clutch.  Anyone who removes the engine to replace the clutch on a 4th gen Legacy should not be performing clutch jobs professionally.

Sorry for your troubles.  Glad you figured it out.  Next time dont have so much faith in humanity, we breed idiots and nature has stopped weeding them out. 

[blackobxt]

This has been surprisingly fun to follow

[thefultonhow]

2 hours ago, m sprank said:

Anyone who removes the engine to replace the clutch on a 4th gen Legacy should not be performing clutch jobs professionally.

I did that twice.

To be fair, the first time I was also replacing the longblock, and the second time I also needed to replace the intake manifold gaskets and install a pressure sender in the oil galley plug, so I figured those things would be slgihtly easier with the engine out of the car. 

Oh, and also, I wasn't a pro

[m sprank]

Not sure how to replace the longblock without pulling it, lol.  Clutch installs were free labor if I was replacing the engine. 

The second time, if you dont have a lift yes it was probably a little easier than fighting. 

But for just a clutch, NO. 

[Bariki]

Interestingly, this issue went unnoticed even when I had to replace the longblock after my timing belt broke (prematurely, I assure you...), so they must have not pulled the transmission with the engine.

I can kind of understand accidentally forgetting to tighten down two bolts before putting the heat shields back on.

It was basically a non-issue between 5 MPH to 70 MPH. I had basically assumed it was the half-shafts because it sometimes seemed to be worse when turning.

[Bariki]

My left rear caliper was so bad I had to use the car’s hydraulics to get get piston out, since compressed air was not enough..

 I hope annealing the used washers was sufficient, since the local Subaru dealer wanted a week to deliver new ones…. Yeah, no. I’ll get new ones if they prove leaky.