Roger, My '79 TD had the rod arrangement but (not being a turbo) there was no vacuum circuit for the transmission.
I have a paper 917.95 engine service manual that may have some clues (or maybe not). I found this vacuum diagram for a non EGR setup that may (or may not) reflect your setup: <http://pt709.synology.me/0.7.1.8-150_3.jpg> I think the valve/cam-plate thing (on the right) is the vacuum engine stop circuit in the key switch. The vacuum control valve appears to have 3 ports. That is quite different from the setup on my '82 SD where the vacuum control valve only has two ports, the restrictor is external, and the transmission vacuum modulator is on the left. On my 82 SD vacuum to the transmission is totally independent from the switchover valves (which only effect EGR). This next diagram: <http://pt709.synology.me/14.8-050_8.jpg> illustrates the function of the switchover valve in the extended and depressed positions and this diagram: <http://pt709.synology.me/14.8-050_4.jpg> shows the internal workings of that valve. The way I read the diagram, the tranny vacuum modulator gets full vacuum at idle/low power but that vacuum gets modulated by the vacuum control valve at higher power settings. Of course, your '80 SD could be entirely different Scott > -----Original Message----- > From: Mercedes [mailto:mercedes-boun...@okiebenz.com] On Behalf Of > rogerhga--- via Mercedes > Sent: Tuesday, October 13, 2015 3:36 PM > To: Mercedes Discussion List <mercedes@okiebenz.com> > Cc: roger...@comcast.net > Subject: Re: [MBZ] 1980 300SD Transmission Problem > > Scott, > My car has the rod to the tranny and not the cable. Again, per Mark at Sun > Valley, it's an "early, simplified" version. The switches on top of the valve > cover are tied to both the IP and the EGR circuit, so I don't think you could > bypass them. My car does not have the EGR, but my 1983 300D does and it > also has the same vac diagram as it appears in the 1980 MB Service Manual. > But my setup is NOT diagrammed in that manual. I have a call into the local > MB dealership to see if they have a correct diagram for my car. As best I can > determine from a good bit of good input, it is probably the green restrictor in > the line going to the IP modulator valve or the IP modulator valve itself. I > hope its the restrictor as the IP modulator valve will be almost impossible to > find for this car. > Best Wishes, > Roger > Roger Hale > Dinnerware Classics, Inc. > Monroe, Ga. > 770-267-0850 > www.dinnerwareclassics.com (new) > www.southernnightsantiques.com (antique) > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
