M1009 TH400 Modulator question

[portert0224]

The GM P/N for the modulator valve is 359917. Does anyone have a good replacement source for these that still allow the stock line nipple to fit into the modulator nipple?

AAP had a replacement, but the modulator nipple was not large enough for the metal vacuum tube nipple to fit. Connecting the two with a vacuum hose sounds simple except my vacuum tube is at an awkward angle to use a rubber vacuum hose. What is everyone else doing?

Second question is: Can the shift speed be adjusted with a screwdriver when the modulator valve is out? On the aftermarket replacement modulator valve that AAP tried to sell me has an adjustment screw in the nipple. The stock modulator valve did not have the adjustment screw in the nipple.

Thanks in advance.

 

[Westech]

just buy one from autozone or who ever and get a small scrap of vac line. no need to reinvent the wheel.

 

[zyrtecx]

All NAPA Stores have them and they are adjustable and come with and "L" shaped rubber hose, the only thing that you have to do is cut the rubber hose to fit... Just installed one on my M1009 and it works fine! Don't forget to install the O-ring in the end that goes in the transmission. Got to be fast installing because transmission fluid will come out of the transmission when the modulator is removed.

 

[niferous]

The O'Reilly part number is VM324 and mine works just fine. It comes with the hose that you will need as well.

 

[portert0224]

Modulator Questions Revisited

I guess my post was not clear. When disconnected from the modulator, my metal vacuum line springs up about 5" (as if the original metal vacuum line was installed 5" short). In order to reconnect it, you must pull the metal vacuum line back down to the modulator and slip it into the nipple of the modulator. Once slipped into the nipple of the modulator, the line is held in place. The problem is that I want to replace my modulator with an aftermarket modulator that the metal line will NOT fit into, so yes, I understand that it needs to be connected with a rubber hose. However, if I simply connect a rubber vacuum hose as everyone here suggests, the tension from the metal vacuum line naturally wanting to spring back up and above the modulator will kink the new rubber vacuum line, thus effectively cutting off the vacuum.

I guess the response I was expecting was a recommendation to bridge the 5" gap with another metal vacuum line that will not kink under pressure.

Second question dealt with how were the TH400 shift points adjusted BEFORE the aftermarket modulators with the adjustment screw came into existance. The original modulator on my TH400 did NOT have a little adjustable screw in it to adjust the shift points. So my question is how was the shift points adjusted on the TH400 BEFORE the aftermarket modulators with the little adjustable screw came into existance?

 

[SPECIALTYLC]

Shift is adjusted with the valve on the Inj Pump.

 

[ralbelt]

Use a piece of 1/4" inside dia fuel line install it with a loop in it, if you still think it might still kink, slide a spring inside it to maintain its shape.

 

[stump]

The point that the trans shifts is adjusted on the injection pump. the modulator in the trans can also be adjusted. look to see a line of paint around the end of the modulator the color of the paint tells what pressure it is suposed to shift at. you should be able to bend your line to the right position just dont try to bend it in one spot. make sure to use good vacume line or it will suck flat and give you more problems.to make the trans shift sooner turn the vacume switch on the injection pump towards the radiator. slower is away form the radiator.

 

[CurbRash]

The O'Reilly part number is VM324 and mine works just fine. It comes with the hose that you will need as well.

Bringing up an old post. I recently (5-15-15) went to O'Reilly's to get the transmission modulator and the part number has changed. They were able to locate it under part# 747001