liquify33

My ‘77 VC has a 403 w/TH400, HD cooling and 2.56 open rear. It was also equipped with the towing package, which just means it has a trailer harness as best I can tell (yes it’s still there). It shifts nicely and smooth once the choke comes off drops maybe 100 RPM no thunk, no jarring at 650-ish rpm. 2k rpm at just under 70 on the highway seems it happy spot in life. And it’s really happy there.

My questions:
1st to second shift happens at about 15 mph
2nd to third around 30-35 mph
if I floor it, rpm jumps to around 2k (stall converter?) and just climbs, ie no downshift.
Are the shift points behavior dictated by governor, valve body, vacuum line or all of the above? Any tips on waking it up just a bit?

I suspect the kickdown circuit (it’s the gas pedal type similar to brake switch) for the downshift issue. The switch is making physical contact at WOT but the signal either isn’t getting to trans or the solenoid isn’t solenoid-ing. Up/down through the gears in traffic is flawless but uninspired. How can I test this without launching the parts cannon?

joe_padavano

First, there was no "towing package". When you ordered the trailer harness you got... a trailer harness. Nothing more. Trans kickdown is controlled by the switch on the accelerator pedal. All it does is send 12 volts to the solenoid in the trans at wide open throttle. Pull the wire off the trans and check for 12v at the connector at W.O.T. with the key in RUN. If you do, the problem is in the trans (likely the solenoid). If not, figure out why the circuit doesn't have power.