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-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-04-2011, 01:08 PM
mespe's Avatar
benzbonz
 
Join Date: Feb 2005
Location: Cleveland, Ohio
Posts: 1,848
Weird transmission Vacuum Problem 1984 300SD

Ok this one has me puzzled. I checked vacuum going to the transmission (unplugged black line and replaced with vac gauge.) I got a steady 21 inches no matter where the throtte was. I removed the round green surge damper and I get 12-2 like I should (12 @ idle 2 @ WOT) and the transmission shifts much better.

So I look at the surge damper, I can blow through it and pull a vacuum through it both directions. So why when this surge damper is installed, I lose my 12-2 vacuum going to the trans?

Anyone?

__________________
Closing the store
Benzbonz.biz
on your smart phone or tablet.
Reply With Quote
  #2  
Old 05-04-2011, 02:20 PM
tyl604's Avatar
Registered User
 
Join Date: Feb 2008
Location: Atlanta, GA
Posts: 3,411
I did not know what the green thing was for but this is an excellent question. Hope someone knows; I do not. But I certainly know how to adjust the vacuum modulator, vav lever, and vav nut under the plastic dome. Got my new tranny almost completly straightened out - 81 300SD.

Good luck - hope someone has an answer. Bet Steve Brotherton knows.
Reply With Quote
  #3  
Old 05-04-2011, 03:44 PM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,634
it is just that - a damper. When vacuum changes suddenly, it smooths out the change so the trans gets an even signal that is better timed and not so 'touchy'.

it is a dashpot, it damps pressure fluctuation. It only 'decreases' flow under severe changes in pressure or vacuum. It does not restrict flow when flow is constant.

the only reason it could be disturbing your vacuum levels to that degree is:

-contamination
-bad rubber connections
-broken (ie.. the plastic somewhere has a crack)
__________________

Reply With Quote
  #4  
Old 05-04-2011, 03:45 PM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,634
I also do not understand why your vacuum increased with it installed. The way you measure has a great affect.
__________________

Reply With Quote
  #5  
Old 05-04-2011, 03:54 PM
Registered Hack
 
Join Date: Mar 2008
Posts: 4,634
also, did you remove any other parts with it? (...a 'Y' or a colored plastic insert)
__________________


Last edited by jt20; 05-04-2011 at 04:51 PM.
Reply With Quote
  #6  
Old 05-04-2011, 07:00 PM
mespe's Avatar
benzbonz
 
Join Date: Feb 2005
Location: Cleveland, Ohio
Posts: 1,848
Did not remove the orifice (sp?) the I pulled the black line going to the trans modualtor and hooked up my vacuum gauge. I might clean it out with brake cleaner and reinstall to see what happens,,, will keep you posted
__________________
Closing the store
Benzbonz.biz
on your smart phone or tablet.
Reply With Quote
  #7  
Old 05-04-2011, 07:10 PM
mespe's Avatar
benzbonz
 
Join Date: Feb 2005
Location: Cleveland, Ohio
Posts: 1,848
OK Cleaned it out with soapy water, reinstalled and I have 12-2 again! Hopefully I've also eliminated the occasional "Clunk" when letting up off the accelerator pedal.

__________________
Closing the store
Benzbonz.biz
on your smart phone or tablet.
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




All times are GMT -4. The time now is 02:19 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page