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 06-11-2016, 03:07 PM
Registered User
 
Join Date: Mar 2015
Location: Houston, TX
Posts: 1
W123 300D Transmission Issues

I've got a beater 1984 300D that I haven't driven regularly in a while. When cold, it shifts just fine all the way up to 4th, although maybe some of the upshifts are a little harsh. Once it gets up to operating temp, the shift points seem to rise unreasonably high, to the point where it never gets out of 2nd when driving around town. It will shift into 3rd if you get it going fast enough (like 5000 RPM), but I haven't driven it on the highway yet to see if it will go into 4th at all.

The fluid level is fine, the fluid looks good (red and non-aerated), and it doesn't smell burnt. Adding a bottle of Lucas Transmission Fix (which has given me good results in other marginally-shifting vehicles) made no noticeable difference. The transmission does have a slow leak, so it's possible it was run low on fluid at some point, but I don't recall it having this behavior immediately before I parked it for a year.

I'm hoping the interior guts are still good and there's just an adjustment that needs to made somewhere (vacuum modulator, bowden cable, etc.). Unfortunately, everything I'm reading about this transmission is pretty complicated and I'm not sure where to start. My current plan is to make sure I still have healthy vacuum to the modulator, but if that's not the problem I'm not sure where to go from there.

Any suggestions?
Reply With Quote
  #2  
Old 06-12-2016, 02:35 PM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,179
My first suggestion would be to pull up the drivers floormat and look under the accelerator for the kick down switch and make sure it's free, or even unplug it.

If that doesn't fix it, open the hood and make sure the Bowden cable is attached to the linkage, and moving freely.


Next I'd drain the pan and torque converter of fluid, and refill with cheap Walmart brand fluid, get the fluid level correct at operating temp on a level surface.

This way you know what is in there.

Next get a bottle of trans-X fluid solvent and drive for a week or so, then drain the fluid again and drop the pan and change the filter and gasket. Refill with high quality dextronIII fluid.

If no improvements are found after this... Consult a transmission rebuilder.
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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 01:30 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