2blu442

I know the mid-1960's cars had switch pitch transmissions. I thought I knew how to identify them by two wires on the electrical plug, and spots of weld on the torque converter. I recently pulled the engine and transmission out of a 1968 Toronado parts car. The transmission has one wire on the plug, but the torque converter has the weld spots. I plan to offer parts from this car for sale, but want to make sure I'm identifying this transmission correctly. Attached are pictures of the torque converter. What do you guys think?

joe_padavano

John, I don't know about the converter, but a 1968 TH425 is definitely not a switch pitch. 66-67 only for that.

2blu442

Thank you Joe!

droldsmorland

Whats the date code on the trans?
Possible it was rebuilt and the wrong part was installed cuz it was the only one available or it was a simple error.

I don't know exactly how the circuit works to adjust the vanes. I assume its solenoid over hydraulic. So a dual action converter would act singular or what ever the default mode is installed in a newer 425. Meaning it should still work. I think the default is the tighter engagement mode.

joe_padavano

The switch pitch system uses an electric solenoid valve similar to the one for the kickdown. The turbine shaft in the front pump is unique for switch pitch applications since it has the high pressure passage that operates the stator vane angle change. No pressure and it defaults to low stall.

Olds64

We'd better see a pic of the front pump of the transmission so Joe can positively ID that as a standard or switch-pitch torque converter.

joe_padavano

The pump won't tell you what the converter is.