BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Mechanical Maintenance: Break-in / Oil & Fluids / Servicing
 
Evolve Automotive
Post Reply
 
Thread Tools Search this Thread
      08-31-2010, 12:03 AM   #1
brandonwuwux3
Captain
 
Drives: Jet black E92 m3 DCT
Join Date: Jul 2010
Location: SOCAL 626

Posts: 696
iTrader: (2)

can anyone help me on this?

Lets say you have a m3 and it was launched around 25 times. will it damage the WHOLE dct system or just wear the clutch? :O
brandonwuwux3 is offline   United_States
0
Reply With Quote
      08-31-2010, 12:35 PM   #2
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Not a DCT owner, but the better question would be how much to replace a worn clutch. Launches shouldn't cause any more damage than a worn 1st gear clutch (there're 2 multi-plate clutches in there), but I don't think it's an easy (or cheap) job since it requires removing and opening the tranny. I wouldn't do any more hard launches if I were you.

I haven't read about anybody replacing a DCT (or even 6MT) clutch yet, so I doubt you'll get a definitive answer on this, but speculation is fun . And I'm sure you'll get better answers than mine. Good luck.
elp_jc is offline   United_States
0
Reply With Quote
      09-04-2010, 04:56 PM   #3
kenwelch
First Lieutenant
 
Drives: 2008 E92 M3 M-DCT
Join Date: Dec 2006
Location: Mission Viejo, CA

Posts: 378
iTrader: (0)

I don’t think the individual parts are available. You would need seals for the front clutch housing, clutch drum to pressure feed, clutch pistons, steel discs, and friction discs. Using RealOEM.com only the complete transmission assembly is shown and the NOT the clutch replacement parts needed.
The complete transmission assembly is listed as:
01 Replacement, dual-clutch transmission GS7D36SG 1 28007842585 $9,749.87

There are new service DCT tools that BMW has released, maybe in preparation for the ability to pull the front M-DCT housing and replace the seals and service the clutches?

The clutches are much like those used in an automatic transmission and should be able to be serviced in the field with the needed tools.
Attached Images
  
kenwelch is offline   United_States
0
Reply With Quote
      09-04-2010, 05:01 PM   #4
saeedg48
Brigadier General
 
Drives: 12 CLS63 + 14 M6 C
Join Date: Nov 2008
Location: Unknown

Posts: 3,499
iTrader: (1)

interesting photo. thanks
better question is; are those clutches as solid as they're suppose to be. I feel like with a DCT you wont do as much damage because everything is computerized. In a full manual (with a clutch) it's probably pretty easy to kill the clutch..
__________________


2008 M3 Sedan + TestPipes + Tune [sold]

2012 CLS63 AMG + P30 Performance Package
2014 M6 Coupe + AMS Downpipes + KW V3
saeedg48 is offline   Iran
0
Reply With Quote
      09-04-2010, 09:58 PM   #5
kenwelch
First Lieutenant
 
Drives: 2008 E92 M3 M-DCT
Join Date: Dec 2006
Location: Mission Viejo, CA

Posts: 378
iTrader: (0)

Quote:
Originally Posted by saeedg48 View Post
interesting photo. thanks
better question is; are those clutches as solid as they're suppose to be. I feel like with a DCT you wont do as much damage because everything is computerized. In a full manual (with a clutch) it's probably pretty easy to kill the clutch..
The DCT clutches are also fluid cooled which is another plus.
But the DCT owners are still durability testing every day.
kenwelch is offline   United_States
0
Reply With Quote
      09-05-2010, 01:08 AM   #6
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Quote:
Originally Posted by saeedg48 View Post
I feel like with a DCT you wont do as much damage because everything is computerized.
Do enough launches and you'd eventually burn them. The only thing the computer is going to prevent is a mechanical overrev, which is a good thing . The computer still has to slip the clutch at every start, and the harder you start, the more wear on the clutch(es). My curiosity with DCT is if the computer slips the clutch constantly when crawling in traffic (let's say 5 mph), or leaves it fully engaged like many of us do to minimize clutch wear. Other than that, gear changes are much quicker on DCTs, so wear concerns are basically limited to 1st gear. My guess is if the clutch can be serviced, it'd be the whole pack (both), even if only the 1-3-5 clutch is worn out.

I say there's no way in hell BMW can get away with charging 9 grand for a tranny when just the clutches are worn out but we'll see soon enough.

Kenwelch, thanks for those pics. Hey, those look like DRY multi-plate clutches to me , but maybe I'm wrong. Motorcycles have 'wet' clutches that look just like that, but contrary to public belief, they're NOT submerged in oil, nor they even touch it in the sump; they only get splashed with it. Now I'm curious how DCTs work in that respect. Good evening.

Last edited by elp_jc; 09-05-2010 at 01:16 AM.
elp_jc is offline   United_States
0
Reply With Quote
      09-05-2010, 07:15 PM   #7
kenwelch
First Lieutenant
 
Drives: 2008 E92 M3 M-DCT
Join Date: Dec 2006
Location: Mission Viejo, CA

Posts: 378
iTrader: (0)

The dual clutches are “wet” design and hydraulically cooled. In the lower picture that I posted the yellow circled clutch unit is out of the transmission bell housing (clutch housing). When assembled it would be moved to the right inside the housing and engaged to the input shaft and the four sealing rings. The “exploded view” cut-a-way transmission has moved the clutch unit to the left for better viewing.

This is from the BMW introduction manual:

“GS7D36SG M double-clutch transmission features:
• Hydraulically operated double (wet) clutches.”

“The pressure required for the clutches is limited to 18 bar. The clutch is regulated by an integrated proportioning valve.
Overpressure protection is ensured by a pressure relief valve.
Clutch cooling is map-controlled using a proportional valve.”
kenwelch is offline   United_States
0
Reply With Quote
      09-05-2010, 09:44 PM   #8
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Thanks Ken. Somebody posted a link to an M3's DCT build with 700HP clutches after I asked a question. It has all the pictures I was looking for to satisfy my curiosity . Man, I don't think I'll ever own such a complicated (and not that reliable...so far) tranny, but the technology is awesome ; just don't want any more crap that can go wrong in my cars. If I have to buy an automatic car, rather lose a few tenths and not having to worry about reliability, longevity, or repairs. Good evening folks. Oh, here it is, enjoy:

http://www.m3post.com/forums/showpos...60&postcount=3

Last edited by elp_jc; 09-05-2010 at 09:50 PM.
elp_jc is offline   United_States
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Forum Jump


All times are GMT -5. The time now is 11:57 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST