So, you've confirmed that you have a vacuum leak somewhere in the system and the modulator is not receiving proper vacuum levels to keep the shifts down at reasonable rpm levels.

Must track down the leak with a Mityvac............

Thank you, Brian. Will isolate leaks this evening. Should I plug the switch under the accelerator back in? What is it called and what does it do? JM

Yes, you can plug it back in. It's a switch to delay the shifts until redline of the engine...........when the driver has mashed the pedal and must have all available power. It's the usual culprit in these scenarios...........but, not yours..........unfortunately.

Hi all!!

Well, thanks to my friend jhooligan, I'm here and glad of it!!
I have my own collection of bikes (BMWs) and cars (many, including an '83 300SD and an '84 300D), but I'm asking this now on behalf of another friend. Dmitri has an '82 300SD that was working perfectly until it suddenly lost all forward motion. He drove home from across town in reverse! Thankfully it was late at night.

Anyway, Jonathan (jhooligan) informed me that the transmissions rarely fail, and often their problems are caused by external control systems. Is there a possibility that Dmitri's transmission might still be ok?? The fluid is full and still looks fine.

Thanks in advance!

Dave

Well, Jonathan is incorrect with his diagnosis. This transmission did fail and it failed most likely due to a B2 piston fracture.

Here is how to fix it.

Brian, thank you so much!!
Dmitri just came in to see what I was so excited about; I told him the story and showed him the posts and the link to repair, and he is amazed and also very thankful!! It's kind of a miracle; very serendipitous, and it's hard to express just how grateful we both are. He will go ahead with the inspection and repair. He did mention that I got the year wrong; his car is actually an '81, but I figured that the information probably still applies.

Thank you again!!
Dave
!!!

Well, don't get too excited. It does sound like the B2 piston, but without an investigation, nothing is assured.

Be very careful with the cleanliness of everything that touches or goes into that transmission. It's highly intolerant of any foreign material. Don't do the job on a windy day. Let us know how you make out.

Hello Brian:

One of the 3/2 valves was shot. Replaced both. Got vacuum. Shifting still too firm on 1-2 and too late on 2-3 (redline). Adjusted linkage on side of VCV and backed off modulator. Shifting very well now -- never this good in the past. Thank you for your help and advice.

Jonathan

Good job.

Had you previously adjusted the modulator to increase the pressure while you were chasing the issue?

Yes. It was turned almost all the way in. JM

I forgot to mention that it was backed off in the last adjustment. In reading the Brotherton article again this morning, I can see that I should start with the modulator adjustment first then follow up with the fine tuning methods. Sometimes on fuller throttle, the 2-3 shift is too long, the 3-2 downshift around 90deg corners is off and there's slippage in the 3-4 shift after full throttle through the 2-3 shift. It's getting there.

Now that I've spent the last several days reading all 44 pages of this very informative thread, I have one question:

Why have all of Sams posts been edited by the webmaster with no reason noted for the editing?

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

In talking to my son's friends familiar with vBulletin, it could be that the webmaster had undeleted posts that were deleted by another?

On one of my airplane building forums, everyone left when it was found out that a moderator edited someones post. And I mean EVERYONE. The owner of the forum is really the only one there now, and this was just for changing a few words in a single post. It was understood by all forum members that all posts would remain as written and they took it very, very seriously.

Anyway, it's nice to have them (the posts) back. Sam has been very helpful in educating me in regards to the vacuum operation of the transmission in my diesels.

Thanks Sam! (wherever you are)

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Just an observation, under his name it says "Banned". Now that could be a custom title that he gave himself, but if he did he has an odd sense of humor.

'Course, my wife says the same thing about me....

__________________
mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

I believe "Banned" means what it says. I think our buddy Sam either went over a line too many times or once too far. If you look at the right side of the header you will see the infraction numbers.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60