I have a chance to buy a 65-66 caddilac 429 with a swith-pitch TH-400 tranny. I hear alot of talk about these trannies and have done a search (with no results). My question is what is a "switch-pitch" tranny? What does switch-pitch mean. A little education would be appreciated. Thanks.
TH400 question
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Sniper
Canadian Rust Bucket
Can't say I had heard the term before. So I Googled "Cadillac Switch Pitch Transmission" and got a whole whack of info. It seems the vanes in the torque convertor were able to shift their pitch so it would have a variable stall speed. A switch on the throttle linkage would give it the info it needed. Sounds like Buick have them in 65 and 67 as well as other makes. Try the Google route, you should find a lot there. Sniper
Gastrick
One of the Dirty Dozen!
I copied this from a S-P site. Here's a link..........................
http://www.paeenterprises.com/
The S-P transmission is a concept that was used in the mid 60's on Buick, Oldsmobile, and Cadillac cars, in which a unique torque converter was used containing a special stator inside. This remarkable stator had moveable vanes instead of solid cast vanes.
What this did was allow a higher stall converter in one mode which would help accelerate the car from a stop, and then a lower more efficient stall in the other mode to allow the car to achieve better gas mileage when cruising.
These converters worked very well and produced torque multiplications in the range of 2 to 1 or better in the high stall position. Unfortunately, they were discontinued because of cost. The S-P set-up was only available on the t-300 2 speed tranny from 1964 to 1967 and the t-400 from 1965 to 1967. We have taken this technology and expanded it to create the ultimate street/strip transmission. You can now have a transmission that will allow you to launch your car like any bonafied racing converter and then, with the flip of a switch, it will give your car the truly streetable driveability of a low stall street converter when you are cruising! In addition to that, this converter also improves mph in the quarter mile by simply turning the high stall mode off once the car is launched and into it's power band. Anyone who has ever tried to drive a big cam on the street knows that you need a high stall converter at stop lights to keepfrom loading down the engine and to keep from creeping at stop lights. Unfortunately, high stall converters are not well suited for street use once you leave the stop light and are trying to cruise. The S-P converter gives you a high stall mode only when you need or want it, and a low stall mode for cruising! It really is the best of both worlds! I have never come across a cam that can't be driven on the street with one of these set-ups. When you combine this S-P feature with the unsurpassed strength and durability of the t-400 transmission, you now have an absolutely bullet proof combination! You can run a numerically lower gear ratio in the rear-end, let the high stall launch the car as if it had larger gears out back and still have good highway cruising characteristics. Let us build one for you.
http://www.paeenterprises.com/
The S-P transmission is a concept that was used in the mid 60's on Buick, Oldsmobile, and Cadillac cars, in which a unique torque converter was used containing a special stator inside. This remarkable stator had moveable vanes instead of solid cast vanes.
What this did was allow a higher stall converter in one mode which would help accelerate the car from a stop, and then a lower more efficient stall in the other mode to allow the car to achieve better gas mileage when cruising.
These converters worked very well and produced torque multiplications in the range of 2 to 1 or better in the high stall position. Unfortunately, they were discontinued because of cost. The S-P set-up was only available on the t-300 2 speed tranny from 1964 to 1967 and the t-400 from 1965 to 1967. We have taken this technology and expanded it to create the ultimate street/strip transmission. You can now have a transmission that will allow you to launch your car like any bonafied racing converter and then, with the flip of a switch, it will give your car the truly streetable driveability of a low stall street converter when you are cruising! In addition to that, this converter also improves mph in the quarter mile by simply turning the high stall mode off once the car is launched and into it's power band. Anyone who has ever tried to drive a big cam on the street knows that you need a high stall converter at stop lights to keepfrom loading down the engine and to keep from creeping at stop lights. Unfortunately, high stall converters are not well suited for street use once you leave the stop light and are trying to cruise. The S-P converter gives you a high stall mode only when you need or want it, and a low stall mode for cruising! It really is the best of both worlds! I have never come across a cam that can't be driven on the street with one of these set-ups. When you combine this S-P feature with the unsurpassed strength and durability of the t-400 transmission, you now have an absolutely bullet proof combination! You can run a numerically lower gear ratio in the rear-end, let the high stall launch the car as if it had larger gears out back and still have good highway cruising characteristics. Let us build one for you.
Rat'l Trap
Well-known member
I bought a 350 Buick, so I spend a bit of time at V8Buick.com. Those guys can give you the inside scoop on the SP trans and converter. Depends on your wants and needs. It may not be the kind of performance you need, or it may make perfect sense for your style of driving.
