I was hoping to find some knowledgable patient people that could help me out. I am relatively new to Buicks and last week bought my pride and joy, a '71 Skylark that a friend build and raced prior to passing away. I am trying to learn my new car and I know it was built with a ton of high dollar stuff. My question is in regards to the switch pitch 400 that is in it. I am not to sure if it is working or not. There are 3 wires with the set up, two that go to a 3-way switch and one to the brake pedal light sensor. When the key is on one wire is hot, when the brakes are applied, 2 are hot. I took the tranny pan off and can hear a click when the brakes are applied. I am unable to ever get the 3rd wire hot, regardless if the brakelights are activated or what possition the 3-way switch is at. Do I have a problem, or is my transmission smarter than I am??? Thanks for your help. Jim
Jim, I'm following the brake light switch idea, but the rest of the description I don't. Can you make a sketch of the wiring so we can see what's connected where? Devon
Sorry I didn't describe it better, I have spoken to several people that were involved with the car when it was built and all are positive it is a switch pitch, not a lock up. The one wire goes to the brake pedal while the other 2, one red one blue,go the the 3-way switch. The red and blue then go from the switch and down to the rear driverside of the transmission. The wires go through a hook up into the transmission just below the valve body. One wire goes to a small black box looking thing on the rear bottom of the valve body, the other goes in front of the valve body, then up towards the pump out of sight. The clicking I hear when the brack is activated is coming from the front. Thanks for your help, Jim
thanks for the help guys, but I got it figuired out. It is a SP 400, not a lock up, but it was set up so every time you hit the brakes it goes to high stall (2200) VS the low stall (1300). After you start driving, or launch from the line about 1 second later the converter puts itself back to low stall, which according to a local tranny shop, alows the transmission to multiply the torque better than when it is at high stall. :beer Does anyone else know of a car set up like this, does it really work? Will the switch in the tranny burn up because it goes in and out hundreds of times in a sunday drive? Also the 3rd line that I couldn't get to show hot was the kickdown. ou:
For consistent racing, a lot of folks use a similar setup so that the converter goes to low stall close to the 60' mark. I use a momentary switch on my column shift so that I can have high stall whenever I want. FYI, I've never had a detent or vp solenoid die on me, even after years of use (and the years of previous owners' use). The detent on your '71 should be energized by a switch above the gas pedal, it might just need adjustment or a check at the fuse block. Devon
That is exactly how mine has been set up for years- no problems. The factory designed the SP so that the car would be more comfortable at idle and not "push" so hard, which is why it was connected to the brakes from the factory. The 3-way switch will allow the user to put the convertor into high-stall whenever he (she) wants. For example at the track, you might until after the launch to put it into low stall, to increase efficiency down the track. Or you might use it as a sort of passing gear deal. By the way, hopefully there is a diode in the circuit so that the brake lights don't come on when you switch into high-stall mode! -Bob Cunningham
Just for clarification, rather than using the brake light circuit, the original setup used a microswitch on the throttle linkage such that whenever the throttle was closed, you were in high stall. Pretty slick actually. Here's a diagram (see view B) just as an FYI for the ST300 setup. I've never seen anything like this adapted to the later A body throttle cable or linkage, though. http://home.comcast.net/~shinzan/ST300_linkage.jpg Devon
Haven't tried to scan that yet, it's part of the three-page foldout diagram for the whole car! I'll try to give it a shot, though. It'll end up being a really big file due to the resolution required. Devon
Thanks for the info guys, it makes me feel more at ease with how it all works, although I think my 3-way switch is bad because no change regardless of brake pedal. Thanks again- Jim Moore :TU:
