Noise from tranny while coasting in 5th

First, please forgive me if this is common and has been discussed before. I'm on my phone today and used the search feature in tapatalk, but anyone who has used tapatalk before knows how weak the search feature is.

 

I noticed this morning that I could hear a faint metallic rattle ish, or almost like air leaking through a window while going fast on a windy day...sound when in 5th gear and with my foot off the gas. When I pressed the gas pedal the sound would go away and if I put the car in neutral the sound would go away. Downshifting to 4th and no sound. Only in 5th.

 

I just filled up and checked my tranny fluid. What a PITA to reach BTW! It was a little low, but clearly within the OK lines. The engine wasn't all the way warmed up either. It's cold today, was 8 this morning and warmed up to the low 20's now. I came out on my lunch break and started my car and let it warm up for 5 min. I then drove .5miles to the gas station so the oil was warm, but not up to full temp so it prob isn't very low at all.

 

I did purchase Extra-S and plan to change fluid, but since I don't have a garage and there's been snow I haven't gotten it done yet. I'm a rather new Subaru owner and haven't owned a car with manual transmission since I was in high school so any help I can get is much appreciated. I will try and catch an audio clip on my phone on my way home.

Got a good video this morning on my way into work. I just listened on my phone and can clearly hear the noise. I have have good enough signal to upload from my phone at work so I'll post it tonight when I get home.

Link to YouTube video. Still on my phone but got to wifi to upload.

 

[ame=http://www.youtube.com/watch?v=fEV-pUddyjU]YouTube - Subaru tranny noise[/ame]

anyone?

I heard it, but it's really hard to tell what exactly it is. Does it only happen in 5th gear?

yes, only in 5th gear. It stops when I pres either gas or brake, or put the car in neutral.

Sorry for asking questions, just trying to weed out possibilities. In 5th gear, does it happen more at higher speeds or lower speeds, or is it the same regardless?

Well the roads haven't been very good and I haven't been anywhere to drive an interstate in the last couple weeks. All driving has been 2 lane back roads or highway so I haven't gone faster than 55. The noise happens from 40-50mph, the only real speed range I've gone recently in 5th

Is the sound more noticable inside the car or with the windows down? Can you feel this sound through the gear shift? The diagnosis is going to be hard to find since it's only that one gear and may have to take it in to the dealership to figure out. The only think I could think of is your 5 gear is loose, worn or debris is caught around it.

 

My only suggestion would be to flush the tranny and try it again to see if it still happens.

Then again, it almost sounds like clutch chatter.

I haven't driven with the windows down... it was 8 this morning!

 

I don't have a garage, but secured access to a neighbors garage Saturday morning to change fluid in my transmission and rear dif. I have some Extra-S here so I'm hoping a fluid change will help.

 

I did notice that while the sound was still there this morning it didn't seem to be as loud and nearly non-existent on the way home... weird. I saw something over on NASIOC about our transmissions being sensitive to tire pressure and making noise if it's off. I did add a couple pounds to each corner a couple days before noticing the noise for the first time. I might have to play around with tire pressure.

Just an update.

 

I replaced tranny and rear deferential fluid with Subaru Extra-S on Saturday. Since then I've put a couple hundred miles on, including driving my daily route to and from work a few days and a trip to Buffalo on Monday. The noise is still present on back roads, but is less noticable when on good roads without any snow cover and I couldn't hear it when traveling at 65-72MPH on 400 or 219. I tried with cruise on and off and didn't hear the noise. I do however get the noise while in 5th from 60-30MPH. I also noticed that the noise momentarily changes when I hit a bump and my suspension moves both sides together.

 

Because the noise is more prevalient on back (not as good) roads and seems to be influenced by bumps I'm wondering if anything is loose and vibrating. What could cause this? Where should I look first?

Holy crap! I think I have the same problem!

 

I can hear a metallic grinding noise too but usually when letting a gear wind down (no throttle but in gear), like before coming to a stop. It's usually when the engine is at 3000-3500 RPM in 2nd or 3rd. If you hear it in 5th, your engine RPM must be around that range also, no?

 

I've been searching the net for a bit trying to find info regarding this.

 

I just had my clutch, flywheel, tranny mount, and cross member bushings all swapped out. Granted there is some additional, expected, gearbox noise, I think the harder mounts make it more obvious than the original poster.

 

I'm gonna try to take a vid myself.

Yeah, I haven't seen another video with a noise exactly like mine. Unfortunately it's getting worse... .

 

Mine doesn't seem to happen so much when up to 60MPH or higher so it's more around 1500-2800RPM I think. I haven't really gotten my RPMs higher than that except on acceleration and I haven't noticed it then.

front diff mine is shot bout to do a 6mt swap

front diff mine is shot bout to do a 6mt swap

 

Do you think? I don't get any binding on tight turns so i didn't think it could be the cause. What other symptoms indicate a bad diff?

The best advice I can give you is to calm down. I went through the same thing with my car last year after installing the kartboy sts. I took it in to the dealership to get the trans looked at under warranty and the worst part was that I was the tech working on it haha. I pulled it apart with 3 other master techs there and found NOTHING! Even replaced the front carrier bearings in the differential, adjusted ring/pinion, replaced the center differential and even replaced the drive and driven gears bearings in the transfer case.

 

The noise stayed the same after all of the work but is clearly a result as manipulation from the shifter in the colder weather.. it seems noise likes to travel a lot easier. It could be that 5th gear doesn't actually sit inside of the transmission's main case that the noise isn't as isolated and can travel through easier along with all of that metal being so cold.

 

Either way... that faint hear noise in 5th is something I just deal with now. If it gets louder or more "grinding"-like then I'll worry but it seems like it's a cold weather phenomenon and a fact of life. Turn the radio up.

That is WIERD. Sounds like fw chatter sorta. Box of rocks on decel but I dont get it - you have a dmfw stock. Thats just strange. Sorry for your trouble!

I'm really not sure what's going on. I found a local person here with the same issue and they said it started once they installed a Kartboy shortshifter. I'm thinking maybe I'll install some new bushings and a short shifter! lol. It hasn't really been getting worse, so I'm not super worried about it.

 

Innovative Tuning in Buffalo said they'd do a drive around with me for free so I'm going to take them up on the offer.

Open up your shifter console/panel and see if the the noise is more audible. Find out if the noise is being transmitted into your engine compartment through vibration of the shifter. The kartboy shifter is definitely noisier than the stock one, and yes, even the shift knob matters for NVH. I have the metallic Subie Momo shifter and it's noisier than the leather wrapped one.

I took the shifter surround trim off and threw on my stock shift knob. I couldn't really hear anything, maybe a little faint and a little bit when I went over a bump. Maybe I need some new bushings somewhere?

Wait, so it's quiet now? Or you meant you don't hear a difference after doing it?

It wasn't making the same noise as before. General noise was a bit louder w/o the trim panel and shift boot but that's to be expected. Last night after playing in a couple parking lots on my way home I got a little bit of rattle when accelerating, but if I touched the shifter the noise would go away.

I just weighed both stock shift knob and aftermarket shift knob on my shipping scale. It isn't as accurate for items under 1lb as the ones at the Post Office so I used a 1lb weight with the knobs to get more accurate results.

 

OEM shift knob: 8oz

aftermarket shift knob: 4oz

 

I'm going to go back to my OEM knob for a few days and see if the problem persists or not.

 

 

I'm thinking the noise is a vibration/rattle/rubbing in the shift linkages and not in the transmission now.

If there is rattle happening somewhere in, on, or around the transmission, the noise will carry though any mechanical component connected to the thing making the noise. i.e. your shift arm could be a vibrating antennae if-you-will. A heavier shift knob will dampen the noise, perhaps. That is the only conclusion I can make. A lot of people run the lighter knobs for more tactile feedback of the transmission, there are thousands of Delrin knobs out there similar to the one you have. I certainly don't think the Delrin knob caused, or is, the problem.

Give it some more time with the stock knob and give us an update. It could also be that, in changing out knobs and removing the console, you wiggled something to make it quieter? Maybe after some miles it will show back up?

 

This is a new thing to me, I have never heard of this before. Good luck in your search for the noise. I will try to help as I can. Shift linkages would be my first place to look.