what line is this?

[rama777]

Their is a black hose that runs alongside the hose that connects the banjo bolt to the switchover valve. It sits in the same clip as that hose. It's black. It runs to the top of the three way hose fitting....The Y fitting had an allen wrench pushed in where the black line is supposed to go. I took the allen out and put the black hose in it's place. It causes the transmission to not change out of first gear properly. When I disconnect it and put the allen wrench in the y fitting the transmission works fine again. What' my problem? What is that black vacuum line?

[rama777]

http://dieselgiant.com/mercedesaldaboostsystemservi.htm
If you look at the third picture, It's the line that runs next to where the banjo bolt line runs from...If that helps.

[rama777]

Anyone?

[vstech]

sounds to me like the vacuum line to the transmission.
it is supposed to flow through a restrictor and have proper flow to control shift pressure on all shifts.
if yours is pulled and plugged to aid the 1 2 shift, adjustments are needed...

[rama777]

what kinds of adjustments?

[JimmyL]

Originally Posted by rama777

What' my problem?

First problem is you didn't tell us what type of car you are referring to. Over a hundred posts and still not in your sig? Tisk tisk..........

User CP > Edit Signature > *type in your year and model* > Save Signature.

[toomany MBZ]

Originally Posted by rama777

what kinds of adjustments?

Yes, please put your car in there somewhere.
Bowden cable is easiest.

[rama777]

About in the middle of the picture. The hose connector has an allen wrench in it. I assume the unconnected black line should be the connection. I'm not sure where it runs as when I follow it it disappears into the car somewhere. When I make the connection, as I said before, the car revs up in first and maybe second gear and doesn't want to shift. Put the allen back into it's place and the tranny runs shifts better. What's my problem? I know someone knows and I know it ain't me....Thanks

[rama777]

...

[theo3000]

It's the line to the transmission modulator, and I bet it's disconnected at the modulator, or the modulator is broken.

[rama777]

Yeah I think it goes to the modulator. It's got a green cap at the transmission end of the line where it fits in. Is that indeed the modulator? As I said, it isn't connected to the vacuum connector and if I do plug it back in, it doesn't shift into 2nd gear right. Just wants to rev up in first gear. Do I need a new modulator or could it be another problem? How do I check if the modulator is working properly? Thanks...

[toomany MBZ]

Originally Posted by rama777

Yeah I think it goes to the modulator. It's got a green cap at the transmission end of the line where it fits in. Is that indeed the modulator? Yes. As I said, it isn't connected to the vacuum connector and if I do plug it back in, it doesn't shift into 2nd gear right. Just wants to rev up in first gear. Do I need a new modulator or could it be another problem? How do I check if the modulator is working properly? Thanks...

I'll have to look up the procedure, but you put vacuum to it, and see if it leaks, I think.

[rama777]

So what does the modulator do anyway? Is the fact that I'm bypassing the modulator a big concern? I plan on fixing the problem when I can but I don't want to hurt the transmission in the meantime.

[turbobenz]

does your tranny shift really hard?


The modulator makes your tranny shift smooth. It leaks vacuum depending on your throttle position which modulated the amount of vacuum going to the tranny.