Tranny vacuum modulator

[MaineShark]

Here's an odd question: how much vacuum is needed to properly operate the vacuum modulator on the transmission? Is it possible, when tinkering with the cam, to end up with too little vacuum to properly operate the transmission?

Joe

 

[JohnZ]

The Chassis Service Manual says the TH350 modulator needs 16" Hg. manifold vacuum to operate properly.

 

[Scooter76]

I would'nt worry too much. Because at the part throttle shift points that are controled by the modulator, you should still have pleanty of vaccum. Even if you have a fairly lumpy cam that doesnt make much idle vaccum it should make enough as engine speed increases. Full throttle shifts are comtroled by the govener which uses rotational speed to determine when shifts are to be made. Hope this helps.