sam and all,

thankfs for the tips. ill defintely look at the old modulator before fooling with putting the new one in. most of this battle will be getting the old one access is tight.

my new green modulator does not have the plastic tee everyone talks about that would lead into the tranny. i dont see where this tee would be - is it already in there?

is there anything to remove in that area to get additional access?

My tranny has a max of 206k miles on it, but I suspect it has less than that. The housing looks really new, but it could just be the fact that the car's from texas. I have the name of the original owner, I have meaning to contact them to find out...I really have been waiting to make sure I have all of my questions in line so I only have to call them once. Part of me is scared to know

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

DD - First take a look at:
http://img.eautopartscatalog.com/live/J5020102311.JPG
and although it is black [ your car has 2 different tranny(s) installed thus the different color modulators that otherwise look the same].
Anyway I note that your modulator litterally "inserts" into a cavity in your tranny and seals with the "O-ring" you see near the tip-end. The black dome cap which you see should be removeable. I don't know if the dome/cap is sealed underneath with an O-ring or not so let us know IF it is.
Now look at:
http://img.eautopartscatalog.com/live/J5020102310.JPG
Since this modulator is green, it is the one your car must have... but this parts photo shows it without the dome and shows the "T" handle/key that is underneath. [Yes, the "T" stays inside/under the dome cap and ALL of the "T" handles (this and prior models to my knowledge) are made of metal, NOT plastic as you indicated]. You partially slide out the “T” handle from it’s fully inserted/locked position and then turn it and the internal adjuster all-thread screw inside the body of the modulator.

Again, use your old modulator to play with and learn from.
I would pump it directly with your vacuum pump and see if you can see it pulling the hydraulic valve that should be visible in the tip that inserts into the tranny.
Remove the dommed cap, and operate the "T" handle/key.
See if you can remove what I suspect is an "all-thread" plastic adjuster screw that moves in and out and acts to limit the travel of the diaphragm.
If you can remove it, count the number of threads it has so you will know how to adjust the new modulator to a mid-way setting.

Let us know how the learning with the old modulator goes BEFORE you proceed with the new one.

As to how to remove the old modulator from the tranny:
(1) again, be prepared with a pan to catch and hold up to 2 quarts of fluid although I don't think you will get more than 1 pint to 1 quart.
(2) remove the cap and "T" handle to give you more clearance room to work and remove the modulator. The "T" handle should just slide out. The modulator must be held in place by pressure from a flange-clamp that is external to the body of the tranny.

The older style modulator like our 1980 models have are threaded with tapered pipe threads and the dome cap does have an O-ring inside for the vacuum line also connects to the cap of mine. I think your modulator design is better for multiple reasons.

Working under the car as you obviously now are... please make sure the car is held up by at least two stands, one stand and a jack, OR best it is on one or more ramps.
That's enough for now...
Regards,

hey all,

to continue the comedy of errors that is my 82 300DT's tranny, I pulled my modulator to find the thing that sits behind it has a broken plastic arm thingie...once again look at the pics (you can see dead VCV parts in the background) i am fairly sure i did not break this, i followed all the guidlines for taking this thing out...

the modulator has been pulled before on my car, and re-installed poorly. the body of it was filthy, and there was some of the rubber transmission frame cover removed to be able to sneak the modulator out. some freestyle wrenching for sure...


So....folks who have some mileage in this area, can you get me a PN for the red thing so I can get it from FastLane. can I replace this thing easily? The answer has to be yes, its plastic...

All additional guidance greatly in this area appreciated...

This is now reaching ridiculous...but I will conquer it...
(Im still having a lot of fun working on it...)

-dd

Attached Thumbnails

     

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Apparently, there are two part numbers for that part there. I don't know which will fit your modulator, but fortunately, Phil should be able to determine that.

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Wow... not what I expected...
... for it looks like you pulled something out of the tranny that crucial... and I'll bet you are homing in on the shifting problem. Let's just hope your tranny's "valve body" is OK... and that IF/whatever something is broken can be replaced.
"H-townbenzoboy" - Do you have a name for this ominus red "thingy"?
I have a manual for the earlier trannies... let me see what I can come up with. I wish you were here, for we have a quality tranny rebuilder business right near the S.F. Int'l Airport and they would know and be a good source IF they knew it might possibly lead to some business for themselves... but Boston is a bit far!

DD - while you are crawling around under there, can you get the numbers off the right side of the tranny boddy... on the flange just above the pan on the
right side IF I'm correct.
Regards,

I have "Plastic Cap with Pin for Modulator Valve", looks like his is missing the pin.

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Sam - I am cleaned up now but its 722.3... Ill grab it next time Im under there.

Do you happen to have a PN for that just to facilitate my conversation with Phil tomorrow? (you mentioned there are two, either one would help...)...

This is the part now where Brian comes in and says "don't worry, that's easy to fix..." I didn't try extracting it, I will get more proper tools for doing that at work tomorrow and make sure that I wont kill something else extracting it...

Stupid red thingy.

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I have
126-277-93-75

and

126-277-05-40

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

I find:
126-277-93-75 is listed as an “AT Modulator Valve Pin” – for $2.65 at:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?header=header.jsp&footer=&product=1262779375&partner=mercedesshop&baseurl=http://catalog.peachparts.com/&clientid=catalog.mercedesshop&cookieid=1WH11JXAQ1YT032GFA

126-277-05-40 – is NOT listed at FastLane nor any OnLine parts houses I checked.

I have a wrinkle... both of these P/N(s) start with “126”…
but this car is a 123 chassis and MOST of the time the first 3 digits are the same as the first 3 in the chassis number!
Regards,

In the spirit of documentation...

Just got off the phone with Phil:

The MB part # for that pin pictured above for the 722.315 tranny is indeed 126-277-93-75, and is like $2.50. I have a green modulator.

It IS easy to replace according to Phil. Just pop out, put in. Feeling better once again, onto the next step of extracting and replacing that thingie, which looks like it wont be too bad.

Replacement questions:

1.) Should I lube everything with a little ATF before putting it in?
2.) As Sam suggested, I am going to set the modulator at some sort of halfway point, does this seem to be a good place to begin? Any help on how to actually set the modulator the 'right' way?

So whats going to go wrong next?

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Just because it's a 123 doesn't mean all parts on it begin with 123. I have parts on mine beginning with 116, 126, 108, even 202!

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

DD – This is a real roller-coaster ride for ya… one that you probably would NOT have taken IF NOT for the FORUM and us prodding you on!

“YES” to 1.) and 2.) above

As to the “red thingie” in your photo:
http://www.peachparts.com/shopforum/attachments/diesel-discussion/39239d1165969115-its-critical-how-you-set-your-transmissions-vacuum-system-your-diesel-mbz-mod-004.jpg … this thing looks like it should slide right up inside the modulator... try it !

Q – Do you have a name for the RED thingie yet? I’m probably repeating myself but in my earlier car's tranny/modulator there was a spring and plunger/rod just inside the hole in the tranny.

COME ON GUYS, GIVE US A NAME… AND A P/N WOULD EVEN BE BETTER !

TownBenzOboy – You are entirely correct… I need to change my CYA qualifier from “MOST” to “MANY” !

the saga contnues...

i swapped out my modulator last night and went for a test drive today. i am very sorry to say it made no appreaciable difference. here's what i did:

-replaced modulator
-put modulator pin in a 'midway' setting
-tested vacuum - modulator held vacuum in car, -vacuum looked good, went down from 10 to 0 at full throttle smoothly like it should
-went for a drive. no big difference. doh. i was hoping for some flaring or smoother shifting or something different now that theres some vac present.

i would have expected to at least have some difference, no matter what the setting of the modulator was as long as it was something.

so what do I do now? i have replaced every vacuum component, finding a problem at every stage. is there anything else i can do at this point? can i more directly test whats going on with whatever recieves the vac signal in the trans?

here's some more info for troubleshooting:
-i drained the trans pan last night. fluid was perfectly red. no metal, burning or otherwise bad signs.
-FWIW my transmission looks new.
-im pretty sure i have bad engine mounts and engine shocks. vibrations at idle, engine throbs a lot went shut off. could this affect anything?
- i definitely have bad rear axles, PO drove on them for a while. they creak when car is being driven at low speeds. dont know if this makes a difference. could this make all of the shifts seem poor?
- is there something else that would make the shifts seems poor?

i have a sinking feeling that i am starting to get into painful territory.

please advise....
dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Getting the modulator to hold vacuum is only the first step. Now that it does, you can tune the VCV. Don't give up the ghost now. Hopefully, additional vacuum to the modulator will soften the shifts.

Adjust the VCV so that it puts out 15-16" to the trans at idle. Then drive it and observe any differences.

If the modulator is working properly, the change in vacuum must affect the shifts.

DD - Don't give up after coming so far.

Clarify how the tranny is shifting when you drive... is it shifting quickly from 1-to-2-to-3... and 4th gears?

IF YES to the above, then take a healthy 3 full turn to the right on the modulator "T" key adjuster.

Regards,