E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > ///M3 Forum

///M3 Forum
The BMW E46 ///M3 is the M version E46 and puts out an amazing 333 HP and 262 lb-ft of torque at stock specs! There are an amazing amount of modifications for both the coupe and convertible models so read up and get started modifying your cars today!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 11-11-2013, 04:13 PM   #1
Alroy
Registered User
 
Join Date: Nov 2011
Location: Michigan
Posts: 99
My Ride: 2003 M3 SMG CWPkg.
WTF is up with the differential backlash?

Seriously, my car has become completely uncomfortable to drive around the city. Is it normal for the car to buck back the very moment you let off of the throttle? It's presumably alot more intense in 1st and 2nd gear. I replaced the center support bearing two summers ago. Never checked the guibo but I still feel like this is a differential issue, not driveshaft.

Maybe I'm just being too picky and this phenomenon is a normal thing for our cars.
__________________
Alroy is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 11-11-2013, 04:18 PM   #2
choxor
Registered User
 
Join Date: Nov 2010
Location: Atlanta, GA
Posts: 4,562
My Ride: JDM
I have no backlash.
__________________
choxor is offline   Reply With Quote
Old 11-11-2013, 04:24 PM   #3
Alroy
Registered User
 
Join Date: Nov 2011
Location: Michigan
Posts: 99
My Ride: 2003 M3 SMG CWPkg.
Quote:
Originally Posted by choxor View Post
I have no backlash.
Any assumptions as to what can cause it then? This only occurs when load is cut off. Subframe? Bushings? Mounts?
__________________
Alroy is offline   Reply With Quote
Old 11-11-2013, 07:22 PM   #4
taylor192
Registered User
 
Join Date: Feb 2012
Location: The Best Place on Earth
Posts: 1,794
My Ride: 2003.5 M3
Re: WTF is up with the differential backlash?

It could be your gas pedal. I have the same problem and noticed it's only bad when I abruptly let off the gas. If I roll off the pedal it's fine.

There is a thread about how to measure if your gas pedal is still good, yet I could never measure mine properly. I'd just replace it if it wasn't so expensive.

Sent from BimmerApp mobile app
__________________
taylor192 is offline   Reply With Quote
Old 11-11-2013, 07:33 PM   #5
M3Froi
Registered User
 
Join Date: May 2013
Location: SLO
Posts: 104
My Ride: 2005 M3 ZCP
I have this as well, I think it's referred to in some threads as the dreaded M3 "shudder." I get that "buck" when I left off the gas pedal abruptly rather than easing off gradually. So far I haven't found a clear solution to this so I'm curious where this one will go. Keep me updated!

Last edited by M3Froi; 11-11-2013 at 07:34 PM.
M3Froi is offline   Reply With Quote
Old 11-11-2013, 08:02 PM   #6
cityjohn
Registered User
 
Join Date: Nov 2007
Location: Los Angeles
Posts: 2,531
My Ride: 2001 M3
Mine does this when I'm in 1st coasting down a ramp (inside a parking structure) but that's pretty much it. Always thought it was because it was cold.
__________________
cityjohn is offline   Reply With Quote
Old 11-11-2013, 09:43 PM   #7
Grinchxvx
Registered User
 
Join Date: Mar 2013
Location: Salt Lake City utah
Posts: 230
My Ride: 2001 M3, 1998 M3
WTF is up with the differential backlash?

I get this too, I feel like it's normal and you just can't let off the gas so suddenly.


Sent from BimmerApp mobile app
Grinchxvx is offline   Reply With Quote
Old 11-11-2013, 09:55 PM   #8
JohnBlaze
Registered User
 
Join Date: Apr 2007
Location: DC Metro
Posts: 7,214
My Ride: Black Sunshine
you might want to get that checked out, bucking sounds terrible
__________________
JohnBlaze is offline   Reply With Quote
Old 11-15-2013, 08:56 PM   #9
Kyemaul
Registered User
 
Join Date: Nov 2013
Location: Queens, New york
Posts: 38
My Ride: 2006 E46 M3 Vert
Can you explain the "buck back" a little more in detail? Is it a vibration or a kick back or do you hear it out the exhaust pipe?
Kyemaul is offline   Reply With Quote
Old 11-16-2013, 07:40 PM   #10
Drewsuph
Registered User
 
Join Date: Jul 2013
Location: Sydney
Posts: 57
My Ride: E46 M3 - E36 320i
A quick check is your Diff mounts. One of mine had come loose and was doing the same thing (in reverse also).
__________________
Drewsuph is offline   Reply With Quote
Old 11-18-2013, 03:28 PM   #11
alirz
Registered User
 
Join Date: Apr 2008
Location: canada
Posts: 229
My Ride: E46 M3 Coupe.2003
yup. Im starting to hate the backlash also.
Its the same thing that causes the "M3 clunk" also. Most noticeable when shifting from 1st-2nd.

I wish the diff was more "tight" so everything felt well connected.
alirz is offline   Reply With Quote
Old 11-18-2013, 04:43 PM   #12
aidan530
Registered User
 
Join Date: Nov 2009
Location: Cumming Ga
Posts: 34
My Ride: e46 m3
So is there a consensus on what the fix is? Does replacing the just the ring and pinion and tightening the lash solve this? Is there anyone that has swapped differentials to a diffsonline or something similar and it has solved it? Even better would a drive line shop be able to adjust backlash/rebuild? I have learned to live with it, but I would love to eliminate it. I've only got 60k miles and its not clunking, but the slack from acceleration to deceleration and back is rather annoying. It also can't be good for the drive line or the subframe mounts.
aidan530 is offline   Reply With Quote
Old 11-18-2013, 05:09 PM   #13
cyberkaa
Registered User
 
Join Date: Jul 2008
Location: Sunnyvale, CA <-- Ithaca, NY <-- dirty jerz (201) Useful Posts: 25
Posts: 136,484
My Ride: E46 332i,M3;E30 325i
Send a message via ICQ to cyberkaa Send a message via AIM to cyberkaa Send a message via MSN to cyberkaa Send a message via Yahoo to cyberkaa
Before you replace or rebuild the diff, have a look at the rest of the components.

Besides the bushings mentioned above, the drive shaft rear CV joint and output shaft inner and outer CV joints will develop a ton of slack over time. It'll feel like backlash in the differential from the cockpit, but the root cause becomes apparent from underneath the car when rotating the drive shaft back and forth. I replaced two M3 drive shafts with 100k+ miles within the last few weeks because of worn CV joints. The output shaft joints on both cars were also loose, but the differential itself had almost unnoticeable backlash.

There is a good amount of backlash in the transmission itself, but that's not worth chasing.
__________________
-Kalim
(klx photo studio)

M3 drive train conversion (S54 Swap, LSD, 6MT, suspension linkage) | UUC Stg 2 Organic Clutch | OEM M-Tech II Kit
KW V2 | BBS GT4 RE | Falken FK452 | Alcon 6-pot 365mm BBK | M3 steering wheel | Powerflex bushings

Quote:
Originally Posted by koven View Post
i'd rather be gapless with no bulge
cyberkaa is offline   Reply With Quote
Old 11-18-2013, 10:55 PM   #14
XIinSC
Registered User
 
Join Date: Jan 2010
Location: Myrtle Beach
Posts: 123
My Ride: 2004 M3 98 M3
Quote:
There is a good amount of backlash in the transmission itself, but that's not worth chasing.
Radial play at the tail shaft? I've been chasing a clunk from the front/center of the car lately. I did notice a good bit of play here. So that's normal as well?
XIinSC is online now   Reply With Quote
Old 11-19-2013, 02:46 AM   #15
cyberkaa
Registered User
 
Join Date: Jul 2008
Location: Sunnyvale, CA <-- Ithaca, NY <-- dirty jerz (201) Useful Posts: 25
Posts: 136,484
My Ride: E46 332i,M3;E30 325i
Send a message via ICQ to cyberkaa Send a message via AIM to cyberkaa Send a message via MSN to cyberkaa Send a message via Yahoo to cyberkaa
Quote:
Originally Posted by XIinSC View Post
Radial play at the tail shaft? I've been chasing a clunk from the front/center of the car lately. I did notice a good bit of play here. So that's normal as well?
There should be hardly any radial play at the output shaft thanks to some pretty beefy bearings and manageable loads of that nature. I'm referring to backlash in the gearset. This causes a high pitched metal on metal clunk even in neutral using just finger torque, which contributes to clutch chatter with lightweight flywheels. I've observed similar lash in transmissions ranging from 8k miles to 100k+ miles. There's one in my garage at the moment with 60k miles on it and sure enough, it does the same thing.

A loud clunk you can hear through the frame, e.g. when shifting between 1st and reverse is usually not from the transmission itself. It can be hard to pinpoint since sound travels through the frame pretty well, but assuming it is from the front, the transmission mounts and flex disc are the first things to inspect.
__________________
-Kalim
(klx photo studio)

M3 drive train conversion (S54 Swap, LSD, 6MT, suspension linkage) | UUC Stg 2 Organic Clutch | OEM M-Tech II Kit
KW V2 | BBS GT4 RE | Falken FK452 | Alcon 6-pot 365mm BBK | M3 steering wheel | Powerflex bushings

Quote:
Originally Posted by koven View Post
i'd rather be gapless with no bulge
cyberkaa is offline   Reply With Quote
Old 11-19-2013, 12:40 PM   #16
///3ME
Registered User
 
Join Date: Dec 2010
Location: San Diego
Posts: 95
My Ride: 2004 M3 SMG
Don't forget about the dual mass flywheel (if you are running one.) They can wear to a point that allows too much radial play, which can give the driveline a distinct thumping upon unloading.
__________________
2004 M3 SMG: V1, Intravee, Custom XM, BSW Stage 1, CSL Brake Upgrade
///3ME is offline   Reply With Quote
Old 11-19-2013, 11:46 PM   #17
XIinSC
Registered User
 
Join Date: Jan 2010
Location: Myrtle Beach
Posts: 123
My Ride: 2004 M3 98 M3
Gonna do the flex joint and CSB next week if we are slow at work. Did the trans mounts already but seemed like I had quite a bit of radial (rotating) play at the tailshaft. Could twist it and get a metallic clink.
Once I pull the shaft I'll look closer, so thanks for the input.
XIinSC is online now   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not 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 On
Censor is ON





All times are GMT -5. The time now is 08:19 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use