Switch Pitch TH400

[zac]

Anybody run one on their 4x4? I’ve collected the parts off two of them, thinking they would end up on a street rod. But I was thinking it might work on my stockish ‘79 K20. Heavy truck with a 350, 32” tires and 3.42 gears. Might help with heavy loads or a trailer. Wondering if it would be worth the trouble.

[Ziegelsteinfaust]

I was told you have to use a BOP case for the switch pitch by my transmission guy. As I wanted him to convert a Chevy one for me, but I ended up using a adapter and a BOP trans to do it instead.

Also the switch pitch is not the strongest converter, and not ideal for towing. If you put your foot far enough in it switches pitch. Which my not be the work right for a 4x4 truck with the extra drag. Even though the concept sounds pretty good.

The vanes are moveable to accommodate the switch pitch. Which is why I would shy away from one myself. I would get a 2000 rpm stall for a truck or get one custom built for what you really have

[chewychevy67]

I had one put in my chevy th400. I believe if the case is older than 79 or something like that the passage is still cast into the housing. Mines on a 2wd and the build isn't complete yet so I have no input of how it works. I do know it makes a lot more heat so I made a switch to turn off the function when towing.

[zac]

Everybody I know uses an electrical momentary switch or button to activate the high stall function when they want it. So coming off the line drag racing you hold the button and then release it to go back to the default low stall at some point. I was going to do the same thing. Hold the button down to get a heavy load going in high stall. The cars these originally came in had all kinds of interesting ways to operate the torque converter, but the high stall function won’t work without an electrical signal.

Yeah, Chevy never offered the switch pitch function, but any earlier case with the passage can be converted. The “passage” just requires a .028 restriction which can be easily installed.

[chewychevy67]

I used a controller from Bruce roe. It uses vacuum front the engine to operate the pitch. More info here
http://www.v8buick.com/index.php?thr...roller.190075/

[zac]

Yeah, I’m going to avoid the aftermarket entirely. Honestly I didn’t know it still existed for this stuff.