Hello everyone, I know this is probably simple for some of you but, for the rest of us, will someone be kind enough to show instructions on what parts do you need (and where to get them online) to build a modulator pressure gauge? (as it applies to 300d's)

Thanks again,
Adiel
83 300D 155,000 Miles

I found some information on how to make it:

This article is borrowed from "David Masinick" a Diesel-Benz subscriber on digest.net and can be found at
http://www.wagoneers.com/DieselBenz/TECH/Trans-Pressure-Gauge.html

With the help of some mailing list friends, I built my own transmission
modulator pressure gauge. The purpose of the gauge is to measure and adjust
the modulating pressure after replacing the vacuum modulator on the
transmission, and to diagnose problems in hard or soft shifting automatic
transmissions. The transmission being tested was a 722.315 series in a 1982
300D. The 8mm connection port to the transmission is used on other models,
but I do not know how widely it applies beyond the 722.XXX series
transmissions. Each transmission has its own specific set point for the
modulating pressure. This information is found in the M-B Technical Data
Manual that covers your particular model car.

Parts:

Qty Description Brand Cost

(1) 0-60 PSI Pressure Gauge 1/4" NPT US Gauge $ 5.00 (on sale)
(1) 1/4" NPT to barbed connector Parker p/n 30282-4-4B $ 3.53
(1) 6'X 1/4" Hi-temp Hose Parker p/n 836-4-RL $16.80
(1) 8mm Banjo Fitting (w/barb) Parker p/n 34982-8-4 $ 5.75
(1) 8mm Hollow Bolt Parker p/n AM-03 $ 1.13
(2) 8mm copper sealing rings Unbranded $ .30
______
Total $32.51

I bought all new parts, but with some scrounging, you might be able to make
your gauge for almost nothing. A 45 degree or 90 degree 8mm flare fitting
might have worked better than the banjo fitting, but I was already invested,
and the flare fitting might also have clearance problems. Doing it again, I
would use 7' of hose, and I'm sure the hi-temp stuff is overkill.

Assembly:

Insert the barbed banjo fitting into one end of the hose, and the
NPT-to-barbed fitting into the other end.
Connect the gauge to the NPT-to-barbed adapter using sealer on the threads
(teflon tape).
Place a copper ring over the hollow bolt, insert the hollow bolt through the
banjo fitting, and place the other copper sealing ring over the hollow bolt.

Hookup and test:

Before doing this work, be sure to clean all loose dirt, etc. from the side
of the transmission and inside the transmission tunnel. You are opening a
passage into the transmission, and you do not want any particles to get in.
The confines of the transmission tunnel make the gauge hook-up a little
tricky. You will find the modulating pressure closure bolt just below and
slightly astern of the vacuum modulator. After removing the bolt, you will
find that the hose off of the banjo fitting must be pointed "up" so that the
fitting can be tightened down. Run the hose up the side of the car and
through the open driver's window. Pressure is tested with the transmission
at operating temperature, with the vacuum modulator disconnected, the
transmission in "D", at 50 km/hr (31 mi/hr).

Good luck!
From: "David Masinick"
a Diesel-Benz subscriber on digest.net