TH400 Switch Pitch -- I am in need of education on this subject ?????

[TURBOPOWERED68]

What is this about?
Two stall speeds in one converter?
How is it activated?
How much power can they usually handle?
How much of a max stall spread can they be configured for?
Does the switch pitch system work for a 98% str 2% strip car?

 

[TexasT]

Yes two speeds in one converter.
This was a thing Buick did stock back in the sixties. But like anything, hot rodders make mods and you get a higher stall. It has to do with the pump on actuation. It has a switch. A lot of people install a second high beam switch next to the high beans and use it to switch stall speeds. That about covers my knowledge. Though I know there is much more. Jim W from the v8buick.com does em. I know some locals here that do em. If you want , the locals ship. Maybe one of our board supporters does em.

 

[mikestertwo]

Switch pitch converters were used on TH400 and 2 speed Jetaway transmissions back in the 60's. My 65' Olds 442 had a switch pitch converter on the Jetaway trans. The TH400 used a 12" converter, the Jetaway used an 11" converter. The transmissions had an electrical solenoid that would change the angle of the stator blades when activated changing the stall speed of the converter.

 

[buicktom61]

Buick did use them on Dynaflow from 1956 until the early 60's.

 

[No disintegrations]

Turbobitt made a way to do this in his trans. Try and pm him and see if he'll share.

 

[mikestertwo]

Buick did use them on Dynaflow from 1956 until the early 60's.

That was actually what was called a Dual Coupling Hydra-Matic transmission. It worked different than a switch pitch converter. Those transmissions basically had 2 converters. A large diameter one and a small diameter with different stall speeds. It would switch between the two which would feel like a gear change. I had one in my 56' Olds 88.