Grinding noise when downshifting

Hi,

 

2005 Legacy GT wagon 5MT. Ive got a grinding noise when downshifting, while the vehicle is still in gear. It disappears when the clutch is in/neutral. Sounds like silverware in a blender. My brother, the PO, replaced the clutch a while back, and that is when the noise started. In his opinion, he did everything correctly except align the driveshaft. So, we took the driveshaft out of its spline and rotated it, and put it back in. We didn't see any alignment marks, so it's possible we got it wrong again. The noise got a little better, but it's still there. It's been bugging me. Any ideas? I'd rather work on it again, before taking it in. But I'm getting close to taking it in. I don't really want a 500.00 repair bill for something I can do. Anyways, let me know if anyone here has any ideas on what it could be, or pics that show correct alignment marks of the driveshaft. Thanks in advance.

Sounds like throwout bearing

The driveshaft or propeller shaft doesn't care how it goes in.

 

So your telling us that when you push in the clutch and move the shifter from 4th gear into 3rd gear, you get a grinding sound. That's bad sycnro's.

 

What fluid are you using in the tranny ?

 

I recommend you only use Motul Gear 300, it's the best thing currently out there for these 5mt's.

 

There is a cocktail mix of fluids that some of the Vendors sell that may help. Google "uncle scotty's cocktail"

No, it doesn't grind when Im putting it into gear. That's clean enough. The best way I can describe it is, let's say it's in 4th gear, I clutch, downshift into 3rd gear, release the clutch, and let it coast while it's in 3rd gear, not touching the accelerator. Like one would do when "engine braking." The noise goes away if I push on the accelerator, or engage the clutch.(neutral) That's why it seems like a driveshaft issue. It almost sounds like it could be a front axle CV joint not greased up enough, but then why would the sound disappear with the clutch in, or the car rolling in neutral?

Welcome to the normal 1940's truck like Subaru 5mt. Both the 5mt's I've had in my wagon make that noise.

 

I have a spare 5mt in the shed, that I'll bet makes the same noise. That decel noise has been talked about.

 

I've learned not to do that, if going down hill just coast in neutral.

 

My DD to work has a long downhill on the highway, I take it out of 5th and coast. On most back roads that I drive if I know there's a long downhill area I coast in neutral. Sometimes I'll coast a mile or so.

Lol.. Reminds me of the joke, guy says to a doctor: "It hurts when I do this." Doctor says: "Well then, don't do that." I guess I could coast in neutral as much as possible, but for safety's sake, I'd rather not. I enjoy downshifting and drifting through a snowy corner as much as anyone else here... I dislike that grinding noise tho.

Guess I was looking for a better solution. Or at least a direction to go in. If it's rebuilding/replacing the whole transmission, maybe I'd wait on that. If it's something to do with the clutch or driveshaft, it'd be easier to tackle. Anyone has a link or an idea, I'd love to hear it. The fluid change might be feasible tho.

I have been through a number of rebuilds with these trannys after some miles the decel noise comes back

Do you have aftermarket or worn engine/trans mounts?

Not sure if I have worn or aftermarket engine/trans mounts... I do know he said that he put in an STI clutch/flywheel. I'll investigate the status of the mounts and fluid he put in. Typically he doesn't use cheap parts, stock/better from what I understand, and he's not a JDM-mod type.

 

Guess I'll baby it until I figure it out. Thanks for your help! If anyone has another opinion, I be glad to hear it.

Assuming you have a 5mt and not a 6mt, how does the STI parts fit ?

 

Is your car a 07-09 Spec B ?

 

 

 

I have replaced the propeller shaft the rear diff, both new OEM and this 5mt was rebuilt by a good tranny shop 3 years ago. I do have a STI tranny mount and Whiteline rear diff mount inserts. When I lift off the gas in 4th gear at about 45mph I'll that noise. At highway speeds when I lift there is no noise. The noise will be ther in 3rd gear too when I lift.

I do have the 5mt, and I'm not sure how the STI parts fit. He mentioned the noise started when he replaced the clutch. But, I believe he also replaced a few other things including a front axle when that job was done. Initially we thought it could be a newly installed dry CV joint making that noise. But since it's a pain to check that boot, I never did.

 

My car's a '05 LGT non-Limited wagon 5mt 290hp. 213,000 miles.

With out being able to hear the noise. I can’t think of anything.

In response to gscw2009 I can't seem to send PM responses... I hope he sees this..

 

Well, I found out my brother replaced the transmission mount with a group N. But he never replaced the motor mounts or pitch stop mount. So, I figured out the extra NVH was from that. I replaced the motor mounts with group N and the pitch stop mount with a Grimmspeed. The noises got better. So that’s what I think it was. Oh, and I also changed the transmission oil with Amsoil.

 

On another note, my center bearing blew and I have to replace the entire driveshaft. I’m not sure if the noise has anything to do with that, but I’ll find out when I replace it and get to drive it.

Did you order the driveshaft from The Driveshaft Store ?

 

I know two other members have since I bought mine.

 

Got yesterday from them.

"Thank you very much for the referrals, we did noticed more order's on this part number last week and I said to myself its got to be because of Byron so thanks again.

 

Steve."

I did get mine from the driveshaft store. And yes, the Grinding noise improved. If you hear a grinding like this and think it could be the driveshaft or center bearing, it doesn’t take much to go under the car and check. Yes, you have to put it on jack stands and weasel your hand in there, or disconnect the Exhaust heat shield and move it a bit so you can get your hand in there and wiggle it around. It shouldn’t wiggle or move, it should be solid.

To put it in perspective, mine destroyed with 237,000 miles on the clock but was probably a bit wiggly for a good 20,000 miles prior. I got lucky, but I can see how it could leave you stranded or worst case scenario, rip through the heatshield or exhaust. I’ve heard of worse things happening, like the driveshaft catapulting the car upwards, but I believe the design here is good enough that it wouldn’t happen like that. But you never know.