My 69 Mustang 428CJ C6 auto changed at 5600 on the dot , every time. I am sure the 429 C6 is the same.
Rich is right, the modulator only controles the shift points at low RPMs. The governer over rides the vacuume at high RPMs. It also controles what gear it will down shift to, at the RPM it is turning. My above Mustang would down shift to low gear at 40MPH and no more.It was geared 3.25. I don't remember the RPMs.
The shift points were as follows with a 3.25 rearend wide open. First to 55-60MPH @5600 Second to 95-100MPH. @5600 RPMs. It would spin in all three gears.
Posted on Jun 7, 1999, 12:07 AM from IP address 206.154.3.82