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 06-28-2008, 12:29 PM
Registered User
 
Join Date: Jun 2008
Location: Norway
Posts: 7
Question 91' W124 300D Automatic shifting hard. IP proportioning valve??

Hi

My transmission shifts quite hard from 2->3, 3->4. 1->2 is perfect. Downshifting (4->3 etc) is smooth and the shifting points is good. Kickdown also etc works fine. It shifts smoother when accelerating really slow.

I have measured the vacum going to the tranny:
At Idle: 11"Hg to tranny for prop. valve, (20"Hg from vacuum pump to IP prop. valve.)
Full throttle: 0"Hg (as expected)

Is 11"Hg of vacuum enough vacuum on a W124 diesel?
The vacuum pump is new and i found no vacuum leaks. The proportioning valve is adjusted for max vacuum to tranny.

Any toughts?
Reply With Quote
  #2  
Old 06-28-2008, 07:05 PM
Registered User
 
Join Date: May 2002
Location: Burbank, CA
Posts: 597
With low vacuum, mine shifts hard with a slight clunking sound. Each time I've had slammy shifts, it's been low vac, with a leak in a valve or line.
__________________
'91 300D 2.5 Turbo 330K
'00 VW TDI Golf, 190K
'67 BMW R50/2
'73 Norton Commando Interstate
Reply With Quote
  #3  
Old 06-29-2008, 02:06 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
What brand of Vacuum Pump?

And how new?

And , I don't think 11 inches is enough...could you be experiencing any leaks?
(Older, cracked from the heat hard plastic lines...same for the rubber connections.)
__________________
'84 300SD sold
124.128
Reply With Quote
  #4  
Old 06-29-2008, 10:10 AM
Registered User
 
Join Date: Jun 2008
Location: Norway
Posts: 7
Question

The pump was installed about a month ago. Don't know the brand yet (don't have the car right here).

Have done a quick check for leaks and didnt find anything. Tried plugging all the other lines and just running one from the pump to the IP valve.. Maby I should do a more thorough test.

Is seems that the vacuum coming from the vacuum pump (20"Hg) is good, but the vacuum from the IP prop. valve to tranny is to low. Is there a chance that the prop. valve is leaking?

may be i should try to tweak the amount of air the prop. valve is leaking into the system by partially blocking the inlet line for the prop. valve??

Does anyone know what the vacuum directly from the vaccum pump is supposed to be?
Reply With Quote
  #5  
Old 06-29-2008, 12:04 PM
Registered User
 
Join Date: Jun 2008
Location: Norway
Posts: 7
Wink

Just cleaned out the little air filter that sits between the vacuum pump and the ip valve, it was pretty clogged. Shifting got smoother, but not silky smooth. Haven't measured vacuum now.
Reply With Quote
  #6  
Old 06-29-2008, 12:41 PM
Registered User
 
Join Date: May 2005
Location: Fernandina Beach, Florida
Posts: 626
Have a look at http://www.peachparts.com/shopforum/diesel-discussion/225697-w124-vcv-20inhg-9nihg-out-ok.html#post1890896

Should be 12" at VCV. but 11 is fine.

Adjust the VCV on the side of the IP (pull it forward to make softer shifts). There's 2 bolts - one above and one below, size 10mm.
__________________
1983 240D Silver/Blue "Sadie", unknown miles. 100k miles on WVO single tank, converted to 2 tank about 10k miles ago, FPHE, Injector Heaters, Aux Fuel pump. Alcohol/Water injection. Frantz oil bypass filter
1992 300D 2.5 Turbo Green/Tan "Jade" 267K miles Stock.
1992 300D 2.5 tan/tan "Rocky" on 2 tank WVO. Pressure actuated Turbo "rat's nest" surgery completed. 197k miles
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 04:48 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, 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