I am hopefully just about finished with my transmission swap from th400 to 700r4....


I want to know how much the pressure changes from the VRV that is used with the TH400 on the side of the Injection pump....I have a after market lockout kit that uses a vacuum switch to unlock the Torque Converter that supposedly needs a 9lb change in pressure to activate the switch (which is supposedly what a GAS ENGINE would recieve from intake manifold vacuum).

In the gas engine when you are locked up and cruising I am guessing that this switch would be activated when the accelerator is no longer being applied and the vaccuum in the intake changes (the vacuum would increase?? when you let go of throttle and butterfly valve would close?)


With the 6.2 with the vacuum pump is the vacuum coming to the VRV always the same or does it increase with changes in RPM of engine?? How does the VRV valve change the vacuum when you let go of the accelerator? when you floor the accelerator?

Sorry, about such basic questions I just don't know.

I have a vacuum tester gauge , if I wanted to find out myself would I put it in neutral and test the vacuum with a bunch of throttle and see the change when letting off??

Thanks for any help understanding this. I do hope the change in Vacuum from the VRV that normally operated the TH400 is similar to what is needed to activate the switch I have (aprox 9 pounds of increased vacuum)

I found a thread where somone posted that their VRV was tested to have had 19" of vaccuum at idle and zero when at 1000 rpm (so increased vacuum when at idle??

If this is enough to activate the switch then it is GOOD.


if not, can a person adjust the VRV?? thanks.