I have had my 84 300d for a month or two, but only now am getting around to working on its problems. Two such problems were (of course) a leaky vacuum system and (probably related) a hard 1-2 shift and a very quick 2-3 shift (meaning it stayed in 2nd for only a few seconds before going into 3rd).

So in digging through my vacuum system I noticed that the line to the transmission was plugged with a bb. I have heard of plugging the EGR that way, but never the line to the trans. I replaced all the rubber hose connections in the trans/vacuum system (basically everything in this diagram) and replaced the plugged up 3-way connector with a new one. there are still some leaks in the 3/2 valves on top of the valve cover even after replacing all the hoses, but it's ok for now.

Anyway, the transmission now shifts much much better. The 1-2 shift is very soft and it stays in 2nd for as long as I think it should before going to 3rd.

Have any of you ever heard of plugging the line to the transmission? I dont want to trade one problem for another. Maybe there is some reason why that bb was there. I bought this car from a little dealer who couldn't tell me anything about it's history.

Also, not related, but I might as well ask. Does anyone have a hint for getting the pressure line onto the banjo bolt nipple. My pressure line was split right next to the nipple so I removed the bolt, and cleaned it out, but for the life of me I can't get the damn line to go more than a little way onto the nipple. The line is really hard and doesn't want to budge much. Am I just a wimp?

Thanks.

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Jackson

1984 300d 223k
1994 Jeep Cherokee 2.5L 88k

"She may not look like much, but she's got it where it counts, kid. I've added some special modifications myself." -- Han Solo

"Would it help if I got out and pushed?" -- Princess Leia

I bet your 3/2 valve are leaking vacuum....I plugged off the lines going to the black box on top of valve cover...no mo leaks up there....bb's work just fine. I am sure you'll hear "pull all that crap off the valve cover and clean up the engiine bay, ditch the EGR valve and block off the hole", and you can! I just wanted that stock look for state inspection reasons...none of that stuff is functional any more, buts it is there to be seen!

Mine now shifts great. Also replace the vacuum connection down on the transmission where it hooks to the vac modulator valve...bet the old one is crap by now.

Plastic line onto banjo bolt....try heating the line in hot water or with a heat gun to soften the plastic and then push it on.

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Mark
1983 300TD Wagon
Even a broken watch is right twice a day

Just to be real clear...there are two lines going to the black box on the valve cover, plug those two lines. The line running from behind the IP pump to tranny should NOT BE PLUGGED.

Clean out that dash pot/orifice, mines a little round green one, just run a very small drill bit or needle through it.

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Mark
1983 300TD Wagon
Even a broken watch is right twice a day

mine are all glued on. and they are almost the exact length for the distance. heating them makes sense, another would be to use a slippery glue to help slide them on, then the glue will harden and keep leaks from happening.
John

I've read that some people prefer the shifting without the vacuum...could be the reason someone put a BB there. Personally, I didn't have any vacuum going to my trans. when I got the car, and in my opinion it's much, much better with the vac. connected. Smoother and stuff. Fewer questions like 'what's wrong with your car!?!'

I'm kinda surprised to hear the car shifts at different times with the vacuum, though (the second shift you talked about). I wouldn't think it would effect that.

I heated my banjo bolt with a lighter for a short time before slipping the line on. You only need to do it for maybe 30-45 seconds, if that. The first time I tried I heated it too much and the line melted when I put it on! I cut that part off and did it again.

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Ralph

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

You can replace the entire line/banjo bolt with a new dealer unit, its very reasonable about $10 to $15.

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

for I too went through a similar purchase and "BB" in the vacuum line, except mine was in the EGR circuit and when the mechanic removed it as part of his initial going over and valve adjustment and when later the car car ran poorly it was I who figured it out. Mine is a 1980 300D CA car that must have had one of the early EGR systems [my 1980 240D has none at all!]. Keep the tranny's vacuum modulator hooked up... I canNOT comment on "Banjos" as I have none!

I would suggest you temporarily plug the EGR system vacuum line and then look down the throat of the intake and see if the valve is open when it is suppose to be closed. Run the car this way too and note if there is any improvement in the acceleration at 55+ mph. If the car's performance improves, then you have to decide whether to repair or use the 'ol "BB" again but in a different place! [ pssst... the EGR line !]
Sam

There are three lines running to the black box.

One is the vacuum supply line that runs from a "T" near the IP. Remove this line, remove the "T" and connect the remaining two lines with a short section of vacuum hose.

One is a vent line that runs to a second "T" near the IP. Again, remove the line, remove the "T" and connect the remaining two lines with a short section of vacuum hose.

The third line is the EGR line and it runs to the temperature switch on the right side of the head. Just remove it completely.

Thanks for all the replies. Good advice for the banjo bolt pressure line.

Here is the problem I have with removing the 3/2 valves from the vacuum system. Namely, these valves are connected in two places to the transmission vacuum control valve on the IP. Do these connections affect only the EGR system, or do they affect both EGR and transmission? That is the question I have. Admittedly, I don't know how any of these valves are designed to function. It is obvious that they take vacuum and destribute it to various other components depending on how the engine is running at that moment. And I know that the whole point of the transmission vacuum system is to simulate the vacuum dynamic that is produced by a gasoline engine. Beyond that, though, I don't know anything more.

However, on parts sites like autopartsworld the descriptioin for the 3/2 valve says it "CONTROLS EGR, INJECTION PUMP AND AUTOMATIC TRANSMISSION VIA VACUUM ROUTING COMBINATIONS."

So I am leery of just throwing away a part of the car which (as described) affects the operation of the transmission.

It seems clear that the transmission will shift no matter how much vacuum it is given. Mine shifted with none. But now that I went and put things back to where they should be it shifts a whole lot better. At least it feels that way.

The black box and EGR valve ARE ugly though.

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Jackson

1984 300d 223k
1994 Jeep Cherokee 2.5L 88k

"She may not look like much, but she's got it where it counts, kid. I've added some special modifications myself." -- Han Solo

"Would it help if I got out and pushed?" -- Princess Leia

I understand your reservations. At one time, prior to 1982, in other configurations, the 3/2 valves did regulate the transmission vacuum and the EGR. However, in your configuration, the valves only serve to regulate the EGR.

I've done extensive testing on that specific system while developing an EGR blocking kit to eliminate the EGR valve itself and you can be fully confident when I tell you that the 3/2 valves have nothing whatsoever to do with the transmission on your specific vehicle.

If you, or any other folks want to completely eliminate the EGR valve, you can check out this thread to see what we've done to accomplish that:

http://www.peachparts.com/shopforum/showthread.php?t=92534&highlight=EGR

I still have plenty of kits available for anyone who wants one.

The 3/2 valves on your model are there to operate the EGR valve. They do not operate the transmission. But, since they are on the same vacuum "circuit" as the transmission, they will affect the transmission if they leak.

so take a look at the following link:
http://www.peterschmid.com/1984_617.htm
There are two different diagrams here and which one you should be referencing depends upon whether your's is a "California" or "Federal" car.

Take a look at and even print both of these out and then take a hard look at each and you should be able to easily determine which car you have by the extra components on the California cars. I hope your's is a "Federal" car.

Let us know what you come up with!

Sam // Novato, "California"

It is definately a federal car since -- from looking at the diagram -- there are no 3/2 valves or little black box on a california. Everywhere I look though I see people taking the whole EGR assembly off their vehicles. Even big powerstroke diesels with EGR coolers. So I may go that route yet. If so, Brian, I might want you to hook me up with one of your kits. I'll let you know.

Thanks for the advise you guys gave. The transmission has been great post bb removal.

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Jackson

1984 300d 223k
1994 Jeep Cherokee 2.5L 88k

"She may not look like much, but she's got it where it counts, kid. I've added some special modifications myself." -- Han Solo

"Would it help if I got out and pushed?" -- Princess Leia