Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 10-11-2001, 09:02 AM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Clunking Sound in C280

I recently had the lower control arm bushings replaced in the C280 because of the popping sound and less steering stability.
But I am still hearing a clunking sound! I am beginning to think that this 'other' clunk might be transmission or driveshaft related.

I hear these popping sounds most often when stepping on the gas (more so when pushing it hard, but sometimes when accelerating moderately) from a standstill, it happens in Reverse and Drive (1st gear). I have also heard it when the trans is dowshifting when I gun it. I think I have also heard it when I'm slowing down (ie, around a corner). But I do not notice any fluctuations in RPM whenever the clunks are heard.

Also, when I hear this clunk when I step on the gas from a standstill, it is also a symptom of my "acceleration resistance" ... only now it sometimes has the added clunk to it.

I did a search and came up with quite a few transmission clunkings, but they were mostly upon deceleration or coming to a stop, while mine seems to be much more symptomatic when accelerating. But I did come up with the possibility of failing flex discs or differential mounts, and maybe even a vacuum leak.

Other than that, transmission operates and shifts just fine, and has also had great maintenance, but it's definitly been worked hard.

What do you think? Thanks for the insight.
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)
Reply With Quote
  #2  
Old 10-11-2001, 10:08 AM
Trex
Guest
 
Posts: n/a
Just a guess:

I had similar problems with a 525i. Motor and transmission mounts were bad. It was an easy fix on the BMW. Hope this helps.
Reply With Quote
  #3  
Old 10-12-2001, 07:22 AM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Thanks Trex,
I am beginning to think it's some sort of "support" related thing that has failed.
I was told to make sure the differential supports were good, as that could be a problem. I do know that 200 lb/ft or torque is quite a bit of turning force, and it only makes sense that something related can wear over time, especially when pushed hard.
Any other ideas?

(BTW, car has 101,000 miles, original trans)

Thx!
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)
Reply With Quote
  #4  
Old 10-12-2001, 10:56 PM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Thanks Trex and John.

So far, the list of items needed inspection are:
Taking Car to Private Mechanic, not dealer.

A) Motor Mounts
B) Transmission Mounts
C) Flex Discs (What are these?)
D) CentER Support Bearings for Driveshaft
E) Differential Mounts

Anything else?

John, if the motor mounts were worn, wouldn't I have a rough-FEELING idle? I did the test and think that the motor mounts are just fine. I could obviously feel the vibration of the engine, and there was the slightest amount of engine movement; I think they're ok. Is it possible for me to inspect anything else? Thanks for the tip.

One more thing, it seems as though the Reverse CLUNK happens about 10% of the time I give it gas in reverse. And when in drive, and I push the gas, it has the resistance about 33% of the time, but the clunk only happens rarely. (This might not mean anything, but I thought I'd add it.

Thanks for the input!
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

Last edited by David C Klasse; 10-12-2001 at 11:05 PM.
Reply With Quote
  #5  
Old 10-12-2001, 11:07 PM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Aghhh, and I bet this is why my car feels squarrely at the 2-3 shift when pushed hard.
But I still do hear random random pops (similar to what I used to hear) if I'm just driving at one sustained speed. I need to have them inspect the new bushings again too, just to be sure.

BTW, I was just kidding!, I thought that may be how they spell it in Canada... I do know that's the proper British way of spelling it.
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

Last edited by David C Klasse; 10-14-2001 at 06:22 AM.
Reply With Quote
  #6  
Old 10-26-2001, 10:00 PM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Yup,
I had my mechanic take a look at it today, and the front Flex Disk is the culprit!
I am having it replaced on Tuesday. I'm buying the part from PartShop for about $60 (vs $100 @ dealer).
Thanks for all the help everyone, I believe that this is the culprit to my "ACCELERATION RESISTANCE"
THanks again everyone.
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)
Reply With Quote
  #7  
Old 10-27-2001, 01:04 AM
Registered User
 
Join Date: Dec 2000
Posts: 368
You don't have to drop the exhaust and drive shaft to change the flex. It usually requires the removal of transmission mount bracket and exhaust bracket. It's a very simple job.
As for the rear flex, they usually never go out. I've never changed one. One of my cars (that I drive very very hard) went thru three (including original) front flex discs. The rear one still looks new. I did however change middle drive shaft bearing as a precaution.

Vinamg
Reply With Quote
  #8  
Old 11-02-2001, 03:49 AM
David C Klasse's Avatar
CheFrac is Back!
 
Join Date: Jan 2001
Location: Mission Hills in the City of San Diego
Posts: 2,352
Flex Disc is replaced!!

ACCELERATION RESISTANCE HAS BEEN SOLVED!!!!!! THANK GOD!!!!!!!!!!!!!!!

No more clunking... after the bushings and the flex disc... replaced!
Car is driving seemlessly and smoothly! I am still amazed at the truly astounding way this car drives... especially at 104k miles.

Also my mechanic showed me something (I asked). I always wanted to know why there was an inlet air vent (in lower passenger side of bumper) that led up to some round thing in the engine bay below the resonator. It was a vent leading air to the motor mount to keep it cool! That's amazing...!
__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
95 c280 bang/bump sound on acceleration barkford Tech Help 1 02-04-2003 01:09 AM
Clunking sound in front of car stacheman Tech Help 2 03-18-2002 12:24 PM
Clunking sound when shutting down can-do Tech Help 3 06-27-2001 10:02 AM
Thumping Sound on 99' C280 FSP Tech Help 1 04-01-1999 11:21 PM



All times are GMT -4. The time now is 09:18 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page