........only if you get to the step where you are removing those "T's" and have no short piece of vacuum hose to connect the remaining tubing..........

After following your instructions, I am pulling roughly 22" hg at the hose that feeds the Y or maybe its a T to the VCV. All of the hoses and T's are removed. I strongly considered pulling the short one from the thermostat housing to the EGR, but figured I should take this one step at a time.

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Chris

82 300SD

Good job.

You will probably get a completely different transmission response, just from that job alone.

But, since we have a new Mityvac, let's do some additional tests:

1) Disconnect the line to the transmission from the VCV (it's tees into the source vacuum). Connect up the mityvac to the transmission and pump it up. See if the transmission modulator holds vacuum.

Remove the Mityvac and reconnect the transmission line

2) Disconnect the source vacuum from the T above the VCV. Connect the Mityvac to the T..........(instead of the engine supplying vacuum, the Mityvac will supply it).

Pump up the Mityvac and it will stop at a certain point. Read the gauge and note the reading.

3) With the Mityvac pumped up, open the rack slowly and watch the Mityvac. The gauge should progressively fall as you open the rack until it reaches zero when the rack is fully open. If the transmission modulator leaks slightly, you'll need to pump the Mityvac during this procedure to get an accurate reading. BTW, none of this will work if you have a big leak in step #1.


Yes, you can take the line from the temperature switch on the thermostat housing to the EGR valve and toss it.

Report back with results.

Once again I have a question, sorry to keep doing this, but by rack do you mean the throtle linkage? Or is there something else?

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Chris

82 300SD

Yes, the diesel engine does not have a "throttle".........it has a "rack" that allows more fuel to be delivered to the engine via the injection pump.

So, you can substitute the word "throttle" which would apply to a gasser..........if you feel more comfortable.

After following step one I found that I don't have a vacuum modulator, its more of a sieve. It apears to hold nothing at all. Which tells me I need to pick up a new one, and put it in, how much fun is this going to be?
I didn't even bother with step 2 since I got nothing in step 1.

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Chris

82 300SD

Which also leads me to my next question, how do I know if I have a California car or not? There is a sticker next to the hood latch that I think says something about the car meets California and US emmisions regulations.

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Chris

82 300SD

OK, that must be corrected first.

The problem may be as simple as the rubber connectors that secure the line to the modulator.

I've not done that job personally, so, I'll defer you to those that have done it on this thread:

trans. modulator location?


You can continue to post here and others will assist with questions until you get the modulator to hold vacuum. Then we can continue with the tests.

Have patience. These things take a bit of time and effort to sort out.

I'm not aware of the specific differences on the '82. Maybe others will have the scoop on that.

a lot of money [$2,000+] in a rebuilt tranny replacement [ at a MBZ dealer it would be well over $4,000 now ! ], and believe me when I say that there are good MBZ mechanics for a lot of the common work needing done on these cars but that does NOT mean they know transmissions... and in particular there is a good chance they will not know how to set up the vacuum control system that helps the tranny decide when to shift... especially if their MBZ training took place after 1985 to 1990. If you try to read and understand the German-to-English service manuals as many on this FORUM have, you would begin to understand how even well meaning mechanics have a real battle on their hands using these manuals as resources for learning. The bottom line is that there are many mechanics that have no idea about how to deal with these vintage of MBZ automatic transmissions... and in my opinion there is a good chance that the one you were recommended by FAMILY is one of these.

GO TO SEE SEVERAL MECHANICS IF NECESSARY... UNTIL YOU FINALLY FIND ONE WHO DOES NOT GIVE YOU SUCH AN OFF-THE-CUFF VERY EXPENSIVE DIAGNOSIS AND STRIKES YOU AS BEING A LITTLE HONEST !

That vintage model car you have needs to be seen by someone with experience in working on these cars and if you do not have someone local enough for you to see, then you should either start learning a lot more about her so you can do most of what is needed or sell her as soon as you can !

I wish you the best,
Sam

The mechanic issue I have more or less figured out. I found a person that can do the bulk of the work that I can't, and I plan on doing as much as possible on this car. I don't know a ton about cars, but I learn quickly, and retain. This car is certainly worth the work, in a way that Fords and Toyotas have not been. If it comes down to it, I will read the service manual in German (I hope I don't have to; that would take a lot longer.) This forum in fact has been a gold mine of information.

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Chris

82 300SD

Q - Have you serviced the tranny's fluid and filter, especially IF you do not know when it was last serviced?

Yes, I have found that these trannies will shift a little " stiff " just after starting first thing in the day when it is still cold but usually this should only last a mile or two.

It might help to know some history on your '82 300SD !

Q - How long you had her?

At some point it's likely you will want to look at the vacuum shift profile under the hood...

Q - Do you have a hand vacuum gauge? [~$40-60 ]. They are invaluable working on so many different vacuum using components on your car.

Sam

I have not had a chance nor do I have the equipment to do the transmission fluid and filter at the moment, although I'm working on getting what I need, and I do have a line on most of what I need, and since I have something else I can drive while I get this car together I'm not going to rush things.
I'm also planning on doing an oil change at essentially the same time as the transmission.
The story I have from the PO, is this, he bought it from his parents, who bought it from the original owner. The title confirms that he had it for only one month, and based on the fact that it was not liscenced during that time, I know that it was not driven. He says that his parents were very good about maintaining the car, although I have nothing to prove it. I took him at his word. (Maybe not the best thing I could do, but, its already done.)

I do have a Mityvac, and with Brian Carlton's help I have found that there is a signifigant leak at, in or near the vacuum modulator. I'm going to take a little mirror, and a flashlight to see what I can see. I might find a vacuum hose just hanging there, or it could be attached, and the thing is just shot.
I know that these cars, as well as many older cars with automatic transmissions can be a little rough cold, but I would like to get this car working as well I can.

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Chris

82 300SD

Also, check the little rubber cap that goes over the modulator adjustment. It is my understanding that this is part of the seal and if it is cracked or missing will give you a vacuum leak.

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Sam

84 300SD 350K+ miles ( Blue Belle )

can start by pulling off the hard line in the engine compartment that takes off and runs down the back of the engine toward the tranny.

You can attach the MightyVac to this hard line and try pumping to see if it will hold a vacuum... maybe you have done this with Brian's guidance... so if it is not holding the vacuum at this connection, tug on the hard line and you might find that it easily pulls right up without any resistance... and if so, you have found your leak. In this case the cause if mostly likely the short rubber line connecting the hard line to the cap on the modulator. So when you do go under the car to check into the modulator, I recommend you also pop-off and remove the plastic cover of the modulator and take if out so you can closely inspect for cracks... and while you are doing this also see if you can get a replacement for the "O-ring" that is associated with this cover. I found that my leaky "O-ring" was contributing to my poor shift problem.

Sam