I’m still struggling with my 1980 300D [na] transmission shifting and not ready to throw in the towel by declaring the tranny hopeless !
I first read on another thread [http://www.peachparts.com/shopforum/attachments/diesel-discussion/32510d1143915823-glorious-orifice-vacuum-sensational-shift-no-flare-123_1.jpg ]
I was given help with finding the proper vacuum diagram. Thanks guys!
See:
http://www.peachparts.com/shopforu...d.php?t=105297
and this link led me to a really good site with diagrams for these vintage vacuum controlled systems… see:
http://www.peterschmid.com/vacuum.htm

Now for the “Eureka” part of this post. Today I went to the local M-B dealer’s parts counter and the first parts man had no clue when I showed him three of the vacuum orifices together with the diagram clearly showing it. His computer listing system was just of no help. Then they brought out a guy from the back room [a mechanic I think] who had his own personal hand-written list. I canNOT guarantee the accuracy but here is the results below. I think this list starts with the largest and ends with the smallest:
Color: P/N:
Yellow……..……..1162760929
Red………………….1162761029
Blue…………………1162761129
White………………1162761229
Green………………1162761329
Brown……………..1162761429
[actually I see the brown as burned orange]
I’m getting a complete set and will use whichever I need or possibly combination I need to tune the system as per the excellent 2002 article by Steve Brotherton at:
http://www.continentalimports.com/ser_ic20242.html
I hope this information is helpful to at least one of you out there!
Regards,
Sam - Novato, CA

I think that blue # will come in handy for me, so mission accomplished. I'm sure lots of others will benefit, too. Thanks for posting.

__________________
Ralph

1985 300D Turbo, CA model
248,650 miles and counting...

My thanks also.

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

Good stuff to know for the slush boxes.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

just a straight thru connector [ Yellow……..……..1162760929 ].

At present I only have Red, White, and brown/orange while I cool my heals for the dealer [hopefully] gets the other three for me. On the InterNet I could only find the yellow one!

I found that the brown/orange reduces the vacuum a bit too much and both red and white not enough... thus my conclusion that one needs to have a full set to have the best chance at getting the proper vacuum balance on the tranny side where the VCV [on the IP] bleed off the vacuum seen by the vacuum modulating valve that sits on the tranny.

I see that later models have what is called a vacuum "dashpot" or "damper" on the line going into the VCV. These are cheap and so I might just give this a try as this should slow down and somewhat stabilize the vacuum the tranny sees as you vary the throttle.
What do you think?
Sam

I believe Peter Schmid prefers the green or brown vac orofice, I can't remember which. He also taught me to check the source tee on the vac manifold (running from the brake booster to the vac pump) by inserting and rotating a small drill bit, about a #60, just a little larger than a big sewing needle, in the port that supplys vacuum to the shifter. In many cases dust or soot accumulates in it and transmission shifting will be affected from poor vac supply. Once you have the vac supply checked, tee a vac gauge off the rigid line that goes directly to the trans modulator. In neutral alternately flip the engine RPM between idle and something like 1500 RPM. The vac should swing between a range that will be set by the variable leak on the back of the IP and the leak in the small colored orofices you are going to buy. Chart the two readings, idle and the most vac it reads and write down the performance after some road tests using individual orofices then tell us which one you prefer. Remember if the trans shifts too soft the clutches wear faster. The shift points on the pre-85 diesels is also determined by the drivers foot on the accelerator pedal, the '85 models use a flying saucer vac device to smooth out the trans shifts (and a different transmission altogether).

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

A very interesting point to note about this test.

You can connect the Mityvac to the supply line before the T into the VCV. Pump up the Mityvac and it will register the vacuum at idle. Then, with the engine not running, open the rack and watch the gauge drop all the way to zero at full rack.

I had presumed that the bleed would dump all vacuum from the pump but, it only dumps down to the setpoint and the gauge then reads the remainder...........the same amount that the modulator will see.

The SD started at 12" and progressively dropped to 0". Since the shifts were a bit soft, I reduced the 12" down to 8". It now shifts firmly but not harsh. It's right on the edge, however. When cold, it will clunk ever so slightly on downshifts. I'm very pleased with it.

Interesting test, Brian! I may do that sometime just for learning experience I still have marks on my vac gauge where Peter put them
The condition of the transmission and condition of the springs on the valve body also contribute to the overall smoothness or lack thereof. A new K1 spring kit goes a long way towards ensuring a crisp shift

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Dieseldiehard and Brian Carlton you are certainly further along the learning curve than I likely ever will be... but actually I think I understood most of your last replies except something that related to springs... and the IP?
I might need to ask you later about that after I have mulled these posts over with my mechanic over beers... that is when he gets back for Hawaii !
Sincere thanks for your replies !!!
Sam

Reid confused you there..........

When he referred to the K1 spring, he went off the topic of the injection pump and switched to the transmission.

Replacement of the K1 spring with the new and updated version makes the shifts much more crisp and eliminates the 2-3 flare in most vehicles.

Thanks Brian... actually I will likely need the info about K1 for after I resolve the power issue, next I will look to the forum to address the 2-3, and if allowed 2-3-4 flare in this 300D's tranny, and K1 sounds like a candidate. I have already started interviewing local [ long-time ] tranny shops.

I have already addressed the vacuum system replacing a couple of defective components and almost have it to "spec".

"Reid" is DieselHard?

Learning a lot from the forum, and Loving...
Sam Ross // Novato, CA

Yep.....that's him.

Glad to help.........