tbjcc001

Need advice on repacement of modulator valve & its vaccum line! Does fluid need draining? Where does vac-line connect on Intake (found disconnected & cannot locate)? Also, what about the plunger & cap components!

RSVP

nsmith17044

I have never needed to replace one but I don't see a reason why the fluid would need drained. However, if you haven't drained all the fluid (including the the torque converter) and changed the filter recently, now is a good time.

The connection point for the vacuum modulator connects at the back of the intake manifold on the passenger side. If you look down between the firewall and the engine just to the right of the transmission fluid stick tube you should see a barbed port that the vacuum line connects to. If it is disconnected, I would get it re-connected before determining if you really need to replace the modulator. If the shifting is soft you can try making small adjustments to the modulator until you get a firm shift (not a jerk or thud).

tbjcc001

Much appreicated buddy!
I've seen a few posts making reference to this adjustment process without specifics (I'll look further). Can you elaborate a bit please! There's a small silver T-Tye pin extending from the Modulator Valve. Is this the adjustment lever?
The Trans Filter was changed & Fluid Flushed via the lines so that's okay!!
RSVP

nsmith17044

Pull the T key out just far enough to turn it. Clockwise should increase pressure, counter clockwise should decrease pressure. My ATSG manual says each position of rotation is approximately 0.4 bar. I would recommend only changing by one or two positions at a time until you get the desired response. If you continue making changes and it doesn't seem to have any effect in the shifting then I would recommend having someone with a gauge set hook up to the transmission and measure the operating pressure (vacuum disconnected, 50km/h travel speed). It is then possible the modulator is faulty or you have a different problem with the pump or governor.

Good luck.