Rear diff clunk / knock - Subaru Impreza WRX STI Forums: IWSTI.com
STI Forum
Join
STI Products
Start New Thread Create Account Advertise FAQ Members List Contact
Go Back   STI Forums > IWSTI Engine & Drivetrain > Drivetrain Components > Rear diff clunk / knock
Welcome to IWSTI - The world's largest Subaru Impreza WRX STI forum!
Welcome to the IWSTI.com Subaru Impreza WRX STI forum.

You are currently viewing IWSTI.com as a guest, which limits your ability to access discussions, ask technical questions, and learn more about the Subaru Impreza WRX STi models. Join for free today and unlock full access to post topics, communicate privately with other members (PM), respond to polls, share content, and access many other special features. Join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see this welcome message.
Reply
 
Thread Tools
Old 05-22-05, 11:48 PM   #1
Ben
Retired Admin
Feedback Score: 13 reviews
 
Fav Mod: Weight Loss
My Subaru Parts for sale

Join Date: Dec 1969
Location: Irvine, CA
Ben is an unknown quantity at this point
Send a message via AIM to Ben
Question Rear diff clunk / knock

I read some other posts about the diff clunking but I'm not sure if it was exactly what I am experiencing.

Basically, what I *think* is my rear diff, makes a clunk or more of a knocking sound quite a bit. In reverse, shifting from 1st to 2nd, sometimes even 2nd to 3rd and 4th to 5th (very very faintly), and even going over the small (higher speed) speed bumps.

Now that I think about it, clunk is really not a good description. It is more like a knock or a pop...

I never heard the noise on my 04 STi or either of my WRX's. There are ways of making it go away, such as taking 3-4 seconds to let the clutch all the way up going from 1st to 2nd, but even then, sometimes when you're not even shifting, just letting your foot off the gas in 1st or 2nd can make the noise.

I'm thinking about taking it to the dealership to see what they say. My TBE is going on in the next week or so, so I should probably go see them before then .

Does anyone else get this noise? I'm sure it's harmless. It's not THAT loud and it doesn't sound like something is broken particularly, it's just more annoying than anything else because I don't know what it is. I'm sure if I just put on the TBE and didn't see the dealer the exhaust would make enough noise that I would never hear it again .

If I had to guess, I would say it's a poorly shimmed ring & pinion, or perhaps even the entire diff housing moving slightly, but I have no idea.

__________________
Ben Fried
RealityDesign

- 2008 Silver BMW 135i
- 2010 Team RD #027 Lotus 2-Eleven Race Car
Ben is offline   Reply With Quote
Old 05-22-05, 11:54 PM   #2
Ben
Retired Admin
Feedback Score: 13 reviews
 
Fav Mod: Weight Loss
My Subaru Parts for sale

Join Date: Dec 1969
Location: Irvine, CA
Ben is an unknown quantity at this point
Send a message via AIM to Ben
Default

Another thing that occured to me:

The noise happens MORE often when you try to drive SLOW if anything. Generally, shifting at 5-7 grand won't make the noise very often. It's when you're specifically trying not to go fast (shifting at 3-5 grand) that the noise tends to occur.

Perhaps my car is angry with me when I am trying to obey traffic laws .

Also, this is not a clunk or knock that you can FEEL, it's just an anoying noise. The car feels completely normal when it makes the noise. I also know for a fact it's not a noise that could have been caused by any mods, as it made this noise the day I bought it with 5 miles on it and I didn't really think anything of it.
__________________
Ben Fried
RealityDesign

- 2008 Silver BMW 135i
- 2010 Team RD #027 Lotus 2-Eleven Race Car

Last edited by Ben; 05-22-05 at 11:58 PM.
Ben is offline   Reply With Quote
Old 05-23-05, 11:07 AM   #3
Platinum Member
Feedback Score: 0 reviews
 
Car: 08 DGM STI
Fav Mod: My wife :)
My Subaru Parts for sale

Join Date: Oct 2003
Location: Ontario, Canada
Digitalfiend is an unknown quantity at this point
Default

The only thing I've ever experienced that is similar to this is when creeping in traffic. I'll begin to let out the clutch, give some light throttle, and when I clutch back in I hear a soft clunk/pop. It sounds like a muted version of the rear-diff slap when you do a quick 1-2 shift at full throttle. It doesn't happen all the time and honestly I think it is just drivetrain slack (at least in my case.)
__________________
2008 Dark Grey Metallic STI
Mods: Stage 1 94 Custom tune | Kartboy f/r shifter & TiC pivot bushings | StopTech SS brakelines | Whiteline 24mm adj. front and 22mm adj. rear swaybars & front brace | RCE springs | Cosworth oil control baffle | STI competition engine & tranny mounts | NGK 1-step colder plugs | Group-A pitchstop mount & front/rear endlinks | MadDad EL header

2009 DGM WRX265 (wife's car)
SOLD - 2005 Aspen White STi
Digitalfiend is offline   Reply With Quote
Old 05-23-05, 11:21 AM   #4
Advanced Mastery Level I
Feedback Score: 0 reviews
 
My Subaru Parts for sale

Join Date: Apr 2004
KingofImports.com is an unknown quantity at this point
Send a message via AIM to KingofImports.com Send a message via MSN to KingofImports.com Send a message via Yahoo to KingofImports.com
Default

Perhaps the extra slop is due to the driver center controlled differential and the various settings that are possible. I know I heard something similar on my 04 before installing my exhaust, gears, and anything else that adds to the noise.
__________________
KingofImports.com is offline   Reply With Quote
Old 05-23-05, 11:23 AM   #5
Advanced Mastery Level II
Feedback Score: 0 reviews
 
Fav Mod: Jr Tune FTW
My Subaru Parts for sale

Join Date: Nov 2004
Location: SC
jays05 is an unknown quantity at this point
Default

My STI is doing the exact same thing.

I first noticed it near the end of last week. Thursday or friday I believe. I thought maybe it was just something in the trunk rattling around so I cleaned the car out completely and the noise persisted. I also noticed that I cannot reproduce the noise by hitting the brakes but I can by downshifting. It's most noticable taking off slowly with the wheels turned, or just about anytime I go into reverse. I get the noise pretty much every time if I let off the gas after shifting.

Against my better judgement I went back to the dragstrip on saturday and made three passes. Car felt fine, and I ran my best ever 1/8th mile and 330ft. But on the way home I launched from a stoplight and felt the back end squishing around.

I am hoping this is an extreme case of rear strut clunk or worn out rear diff mount bushings and not a problem in the diff. Please Ben, bring your car into the dealer... I have a TBE, Intake, and Cobb Stg2... I don't want to return to the dealer unless I really have to.
__________________
2005 STI - 11.0 @ 124mph on 93oct - 10.7 @ 132mph on 116oct
jays05 is offline   Reply With Quote
Old 05-23-05, 11:34 AM   #6
Advanced Contributor Level 2
Feedback Score: 0 reviews
 
Car: 03' EVO VIII
Fav Mod: Moton Clubsports
My Threads
Posts: 240
My Subaru Parts for sale

Join Date: Jun 2004
Location: Granada Hills, CA
ChrisF is an unknown quantity at this point
Default

I have it too. Posted a thread about it. I have now also observed this in my friends '05 STi. I think I found a way to reproduce this as well:

Jack the rear of the car, and rotate either rear wheel left then right. On my car, I could hear a milder version of the same knock. It is constantly reproducible when loading / unloading the diff. This is why we notice it in reverse or on downshifts.

I took it to a local trusted mechanic (Suby Specialties) and they told me it was not normal. I'm waiting on taking it to the dealer for now due to the lack of any local service that I trust. I have trolled here and NASIOC trying to find other people with the same problem, and hopefully even someone who has it who understands our diffs. So far, no luck. I guess I will only feel comfortable when someone cracks my diff, checks the lash and gears and says "it's within tolerances and is normal". I don't expect this from any of the local dealers though.
ChrisF is offline   Reply With Quote
Old 05-23-05, 11:39 AM   #7
Advanced Mastery Level II
Feedback Score: 3 reviews
 
Car: 05 Subaru WRX STi
My Subaru Parts for sale

Join Date: Nov 2004
Location: Frisco, TX
rasetsu is an unknown quantity at this point
Default

I have this too. I think it's normal. When I put the clutch in all the way and let it up easy after shifts, I don't get the clunk.
__________________
2005 WRB on gold

rasetsu is offline   Reply With Quote
Old 05-23-05, 11:42 AM   #8
Advanced Mastery Level II
Feedback Score: 1 reviews
 
Car: 04 STi
Fav Mod: Motor Mounts
My Subaru Parts for sale

Join Date: Oct 2004
Location: Eugene
polyol is an unknown quantity at this point
Default

Normal...
polyol is offline   Reply With Quote
Old 05-25-05, 02:27 PM   #9
Advanced Contributor Level 1
Feedback Score: 0 reviews
 
Car: 05 Stizzle
Fav Mod: MagnaFlow Ti
My Threads
Posts: 134
My Subaru Parts for sale

Join Date: Jun 2004
Location: SoCal 818
xtian67 is an unknown quantity at this point
Send a message via AIM to xtian67
Default

I may have the same annoying problem.

Ben, Chris or anyone in the LA/SFV area want to meet up and compare?
__________________
05 Obsidian STi - Clear Bra, KB SS, K&N Typhoon, MagnaFlow Ti Catback, Helix Catted DP, Tanabe GF210 (TGF107), AP stage 2, Defi BF Boost amber + version II unit, falken azenis RT615, JDM rear spats, V Limited CF replica Lip, 35% all 5.

mazdaspeed3 - white
xtian67 is offline   Reply With Quote
Old 05-25-05, 02:35 PM   #10
Ben
Retired Admin
Feedback Score: 13 reviews
 
Fav Mod: Weight Loss
My Subaru Parts for sale

Join Date: Dec 1969
Location: Irvine, CA
Ben is an unknown quantity at this point
Send a message via AIM to Ben
Default

I'm going to go drive another brand new STi and see if it makes the noise and also have my mechanic at the dealer hear it. I'll let you know what they say. I'm in the valley if you want to compare noises. Just send me a PM.
__________________
Ben Fried
RealityDesign

- 2008 Silver BMW 135i
- 2010 Team RD #027 Lotus 2-Eleven Race Car
Ben is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help? More

All times are GMT -8. The time now is 04:54 PM.


Powered by vBulletin
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Designed & Powered by Domain Architect
Privacy Policy