Well here we go again. Thanks to those who helped out last time. I was able to find a used switch and cannibalized, the triangular shaped contact points inside that were less worn than mine. It worked great for a time, but has died again. I was going to use a B&M #20297 kickdown switch. When I looked in their catalog it says that switch is for a 68- 71 442. It seems this switch should have one more position to operate the switch-pitch torque converter. Placed a call to B&M and asked if this switch would change the pitch of the blades in the torque converters as well as down shift the tranny. The guy I talked to had no idea what I was talking about. Anybody with a Switch Pitch TH400 ever use this B&M part?

Thanks.

 

The B&M switch will not work the switch pitch, only the kick down.

 

😂

Now you need to ask them about a kit for their original B&M Hydro. My guess is you'd get another dumb look!

I think cfair on here has successfully gotten these switches operable again. See if he has any insight.

 

I have a post here on opening these and fixing them. Dig around under my username.

The big trick is soldering the worn parts of the brass contacts back to correct, consistent height to reestablish the switching function as intended. If one contact is high or low, it may the switch not work correctly. I put a dab of solder on the worn part, then file it back to correct (or at least consistent) height. If you get the contact heights right, when you put the switch back together, they’re all in contacts with the brass arcs.

The reason I mention it here is that getting it work correctly took a couple of tries.

Chris

 

Howdy Chris,

It was your EXCELLENT response and photos that led me to try to repair the switch last time. If this was an English car I'd already be geared into the 1 to 3 ratio; drive it for an hour and work on it for 3 hours. I'm most likely going to put this B&M switch on it and enjoy driving the car. I sure do appreciate your help with this, obviously not your first rodeo.

All the best,

Dwight

 

If you post a pic i have 65 - 67 complete switch pitch units and may be able to match a 67 as i forgot to lable them

 

I spoke with Holly tech support (3 agents, each had different knowledge levels) and the quote the instruction sheet, only connect the switch to the vehicle downshift spade on the connector. But I don't know why you couldn't experiment with two wires running from the switch to both the horizontal and vehicle spade connectors. The original transmission control switch ran two wires down to the boot and was applied with a single 12v hotwire. Has anyone tried that?

 

The 67 harness in that area takes two wires down from the rotary throttle switch to the two spade connector on the side of the transmission. The wires provide separate and independently controlled 12V activation signals to solenoids inside the transmission. The black wire provides 12V to activate the switch pitch high stall, and the white wire activates 12V for the kick down. The B&M kick down switch will activate the 12V at anything about a high throttle position setpoint for kick down to a lower gear. You could use the same 12V wire to trigger high stall as well at the same time, but you would miss out on what I believe is the primary benefit of the switch pitch. The low rpm switch pitch activation by the OEM switch make it easier to drive the vehicle around town (less torque converter drag and creep at stops) and it also multiplies torque for launching and improved stoplight to stoplight performance.

If you can't find a replacement OEM or rebuild an OEM throttle switch you can replace each function with separate switches/controllers. The B&M kick down switch will get you kickdown covered. The separate switch pitch control had the high stall kicking in for part of the pedal travel at low and med/high throttle positions. Search here on Classic Oldsmobile on Bruce Roe switch pitch controller and you will find his contact information and a description of his electronic controller. It uses a vacuum sensor, a brake pedal sensor, and timers to do a better job of handling the control of the high stall position in the switch pitch TH400. Your search should also turn up the generally positive feedback from users regarding the Bruce Roe switch. It is well engineered for the typical classic car use case, but for high performance and racing a simple manual switch may suffice.

 

You're resurrecting an old thread.

Holley doesn't know **** about Oldsmobile transmissions. They're a carb company. The OP is long done with his issue by about 4 years. Holley doesn't want anyone doing anything that they don't know on their advice. They know kickdowns. The throttle switch in these cars is 12V in, 12V out on the kickdown when floored, and 12V out on the the converter when at idle and at some point of heavy throttle and higher.

 

Koda is correct. Don't expect any aftermarket company to have a clue about how these systems really work. And as I wrote to you directly, there are a couple of problems with the aftermarket switch. First, I doubt it has the current carrying capacity to operate both solenoids. The physical size differences in the switches should be a clue. Using the switch to operate a relay that operates the solenoids solves this. The bigger problem is that it won't operate the converter at idle, when you really need it with the V6. If you wire both together for high throttle use, then they will also be wired together if you do connect an idle switch, with is not what you want. This is why the OEM switch used different sets of contacts. An exactly what is wrong with your OEM switches? Are you having difficulty connecting to the non-original carb? Also, it isn't necessary to spam the forum asking the same question in three different threads.