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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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Discussion Starter #1
on one of my diesels (84) the 3/2 switch has been inop due to worn levers for some time. they are on order btw. for the first month or so i simply unplugged it from the vacuum lines and drove it as is. obviously it shifted a little hard and sort of clunked a little while slowing down, condition normal.
however, decided to plug the open vacumm port that feeds the 3/2 switch the other day and the car now acts just like my other one. the idea was to force that vacuum to the modulator instead of atmoshere, whatever the case, upshifts are perfectly smooth, downshifts are smooth as silk. the only issue that i have is that it seems like when shifting from 3 to 4 the rpms go a little higher before it shifts. like you have to let off the throttle a little to get it to shift for normal driving. that condition has always been there btw.
so my question is, what purpose does the switch have?
 

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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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1,252 Posts
Discussion Starter #4
EGR??? why the steps in the throttle linkage? why do people even bother buying new levers? i thought it had to with throttle travel and shift patterns due to the steps on the teflon "half wheel"
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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I've taken out of the loop on both cars, I understand many folks do as well.
 

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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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1,252 Posts
Discussion Starter #6
i took egrs off both of mine a long time ago. i dont see why benz would put such a complex system to do with egr. it looks like it should do something with the tranny.
 

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1981 Mercedes 300D
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1,249 Posts
I've studied the vacuum lines through the switches on my '81. (I'm not sure if there's a difference with your model year) It appears they made this complicated system to control when the EGR should and shouldn't operate.

For instance, the valves cut off vacuum to the EGR during closed throttle (idle) and WOT.

In preparation of my full EGR removal, I've bypassed the switches. Now I've got a vacuum line going to one side of the vacuum valve on the injection pump, and the transmission modulator line on the other side of that valve. The tranny shifts great!

i took egrs off both of mine a long time ago. i dont see why benz would put such a complex system to do with egr. it looks like it should do something with the tranny.
 

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money pits of various forms
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Remove it and the EGR :)
 

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'73 450SL, '83 300CD, '01 E320 4matic
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In preparation of my full EGR removal, I've bypassed the switches. Now I've got a vacuum line going to one side of the vacuum valve on the injection pump, and the transmission modulator line on the other side of that valve. The tranny shifts great!
:thumbsup: I had to remove all that crap to get the tranny shifting right. The switches themselves were leaky, and the lines inside the little 'box' were all dry rotted.

Everything works much better without that system in place.
 

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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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Discussion Starter #11
here again i go about diesel giant... correct me if i am wrong, but i remember he was selling the idea on his website that if your tranny wasnt shifting right the culprit was those little levers on the 3/2 switch. i believe you guys, i just know that i would not have blinked for a moment removing all that crap a long time ago had i known that it was all about stupid EGR! thanks for the info.
 

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money pits of various forms
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here again i go about diesel giant... correct me if i am wrong, but i remember he was selling the idea on his website that if your tranny wasnt shifting right the culprit was those little levers on the 3/2 switch. i believe you guys, i just know that i would not have blinked for a moment removing all that crap a long time ago had i known that it was all about stupid EGR! thanks for the info.
If the 3/2 valves leak you transmission is not going to shift correctly (vacuum leak). Remove it and be happy. I hear a .25 piece fits under the egr quite nicely.
 

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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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1,252 Posts
Discussion Starter #13
yeah i made a plate for both of mine a while back. i see why DG sells the levers. i take back my frustration....
 

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money pits of various forms
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Worked well enough for me 4x over.
 
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