Hi all,

This evening I replaced all the underhood vacuum connectors in an attempt to eliminate the downshift “clunk” that I’ve read could be caused by a vac leak. Prior to today, door locks, climate control, and engine shut-off all worked well. The transmission had a harsh 1-2 shift and flared on the 2-3, but was fine to drive.

Now, after replacing the connectors, the trans slams into all gears. I’ve double-checked all connections and confirmed that the line to the transmission is still in place (though the car shifts like there's no vac getting to the trans at all--the tires squeal on the 1-2!). No change to any other vac components.

Any ideas on what I might have done here?

Thanks,

Charlie

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

hook a vacuum gauge up to the trans-line and see if you get immediate pressure after engine start.

Admits, sheepishly: I don't own a vacuum gauge.

Declares, resolutely: I will buy/borrow/steal one tomorrow.

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

Do you still have all the vacuum lines connected to the black box on the top of the valve cover?

Do you wish to completely eliminate the EGR vacuum system from this vehicle..........permanently and forever?


If you answer "yes" to both questions, I'll fix your shifting problem for you in about 15 minutes.

Thanks, Brian, but I've already removed the black box vac lines and EGR lines (for testing purposes, of course, as described in your extremely helpful post).

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

Then, you'll have to obtain a Mityvac and search for the vacuum leak. Clearly, the modulator is not getting any vacuum...........so, either it's a leak or the VCV is NFG.

Thanks, Brian. I'll keep my fingers crossed for a leak I didn't "solve" tonight with the new connectors, since the shifts were tolerable before I started messing with things...

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

I do have a vauum pump/gauge and I would be interested in reading the article. Any chance you could send it to me or point me in it's direction?
Darrell

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Darrell

1984 300SD "Ole Girl"
207K

Are you anywhere near Charlestown? There is a very skilled member who lives there and would certainly help you.

vac gauge-$30@AutoZone (genuine MityVac). . .one of my best investments in the pursuit of Benz'n. . .

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". . .back before accountants designed cars"

-Current Stable-
'78 MB 450SL-C 107.024.12.020783 #3840 <Kayleen>
'85 FORD F250 6.9L Diesel <Allison>
'98 Lexus ES300 <Rachel>
Long Gone...
'74 Chevy G10...........................'99 GMC Yukon 4X4
'83 Chevy Suburban 6.2 diesel .....'99 SAAB 9-5
'90 Mitsubishi Eclipse GS............. '01 Chevy Tahoe
'98 Nissan Altima .......................'02 MB ML320
'88 Chevy Suburban V2500 4X4 6.2 diesel

Brian, Charlestown is a little over an hour away... definitely open to a short trip...

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

bbboomer, here's a link to Brian's post:

http://www.peachparts.com/shopforum/showpost.php?p=1375506&postcount=5

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

Contact "BrierS" on this forum. Tell him I sent you...........

Done. Thanks again, Brian!

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

Proud owner of an '82 300CD, here. I too have transmission questions.

I have 10 inches of vacuum at idle going to the transmission and it drops to about 5 inches at half throttle until moving back up to around 8-9 inches at WOT. I still have the EGR and 3/2 valves connected. I actually replaced the 3/2 valves and was wondering what could be the cause of the vacuum reading increasing as I move towards WOT?

I did the ice-maker-water-line-shut-off-valve trick to attain the 10 inches of vacuum and I adjusted the pressure modulator (722.315 tranny) to close to 42.5 psi down from 70 psi. The hard shift from 1 to 2 disappeared, the flare between 2-3 got better and I definately have a faster, more enjoyable car now. The Bowden cable is as close to a no-slack position as I can get it.

My second question is why do I still have flaring between 2 and 3?