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 > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-04-2012, 02:05 PM
Registered User
 
Join Date: Dec 2007
Location: NorCal
Posts: 1,332
Transmission shifted harder at altitude?

I recently drove back to Colorado from California. The transmission in my 300E was shifting VERY firm at altitude, not banging into gear, but it was "kicking" a lot harder than normal especially at redline. Very worrysome, especially since It turned 200K on the way out, was just waiting for *something* to go wrong. The car lived at altitude for 20 out of it's 21 years, so it should be used to it.

Anyways, I'm back at sea level...and it shifts like butter again. Weird.

__________________
http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Last edited by JohnM.; 08-04-2012 at 02:54 PM.
Reply With Quote
  #2  
Old 08-04-2012, 05:18 PM
Hirnbeiss's Avatar
ich fahre, also bin ich
 
Join Date: Mar 2002
Location: South Florida
Posts: 1,671
Given that transmission modulation pressure on your model is controlled by engine vacuum, this is a not unexpected result:
Effects of Atmospheric Pressure on Vacuum Level
__________________
Prost!
Reply With Quote
  #3  
Old 08-04-2012, 05:41 PM
Registered User
 
Join Date: Dec 2007
Location: NorCal
Posts: 1,332
Interesting. I kinda figured it had something to do with vacuum/altitude. Does the modulator self-adjust itself after awhile, or? It never shifted like that at altitude before in the five years I've owned it...
__________________
http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...
Reply With Quote
  #4  
Old 08-04-2012, 09:09 PM
ps2cho's Avatar
Registered User
 
Join Date: Jun 2006
Location: Chandler, Arizona
Posts: 3,525
Its a set value. Over time the engine will lose vacuum, so it may need a SMALL adjustment to compensate for the lack of engine vacuum you have today compared to a long time ago.
__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k
Reply With Quote
  #5  
Old 08-05-2012, 02:07 AM
Registered User
 
Join Date: Dec 2007
Location: NorCal
Posts: 1,332
Well thank god I don't live at elevation anymore. 20% power reduction is no joke. The first pass I tried to make on a two lane road in Colorado scared the sh!iat outta me!

__________________
http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...
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 05:13 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, 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