Switch-pitch

Have an aquaintence selling or trading a switch-pitch TH400. Never looked into something like this until now, but am curious. If I were seriously going to consider this trans, what am I going to need to ask or look for to determine if it's worth my while? Whats something like this worth and most important, WHAT THE HECK IS A SWITCH-PITCH and how does it work and why would I choose it over a regular TH400?
Aloha,
Scott

 

First thing I would ask is the trans works and if the fluid is not burned. Next, get the ID tag information and research what the trans started life as. If the trans was rebuilt or converted to switch pitch, get the particulars on that work(date, who did the work, where the parts came from, etc). Next, inquire about the converter. Again, if this is a TH 400 converted to switch pitch transmission, find out if the converter had the upgraded sprague, who built it, etc. The early reproductions had weeker spragues...

The next obvious inquiry is what sort of life has it lived....

Next, what value is the current owner placing on the setup?

There is a lot of information on the switch pitch transmission if you search the forum.

If I own a BUICK with an TH 400 transmission, it will always be a switch pitch.....:TU:

 

Scott, here is my "keep it simple" explanation.
Switch pitch tranny has a switch activated variable pitch torque convertor. So it has a high stall and a low stall. You can activate the switch many ways. Tyler uses a button on his shifter on the race car, and activates it to launch the car at the line, then releases switch at the 1-2 shift. Our switch pitch convertor has about 4000 stall on the high side and 1400 on the low.

Ask what the high and low stall are on this one you have the chance to buy and make sure you have all of the switches for it. It is basically a turbo 400 so you need the wot switch on the gas pedal also for the kickdown.

Ours has done good for us, but we are pulling it and going to a turbo 400 with fixed pitch for the race car. We might be selling ours too.

Why would you choose it? Better stall for take off, and then it locks in for more mph. Less slip, maybe even better fuel economy on highway?

 

How exactly is you SP switches hooked up i have mine hooked in to my brake switch and have a seperate momentary switch on the consouleto keep the high stall in place longer ? Why the WOT switch and the kick down switch ?

 

The wot is the kickdown switch for the 400. We have the SP switch on a manual button, push for high stall, release for low. Used it on the street that way also, then it's available on command. Lots of people have brake switches with a timer.

 

Just in case it matters. I will probably never run this car at the track. Just a semi daily driver so the launch isn't an issue for me.
Does this mean I shouldn't be looking at a switch-pitch tranny?
Or do the switch-pitch trannies offer benefits for daily drivers as well?
Aloha,
Scott

 

The variable pitch setup really shines on the street when running a big cam. You have the luxury of additional stall which prevents forward creep at the light due to a higher idle speed, and lets the engine rev more quickly into the cam's power band. Also, low stall while cruising is more efficient, and doesn't heat the transmission as much as a fixed pitch high stall converter.

Devon

 

Thanks Devon, but the cam I am running is the TA Performance C-110. It's a mild cam, just a step above the Stage-1 stock cam.
Very mild. Check the specs. Now is it still a good idea to get the switch-pitch?
Not trying to talk myself out of this tranny, just want to make sure it's a smart choice.

 

Great street transmission for daily driving and misc. romping about, and IF you go to the track, you are in business. BUICK originally engineered the transmssion to absorb the rough idle of the big cam cars so they did not sit lurching along at stop lights / signs. Hence connected the solenoid to the brake pedal so when the brake pedal was depressed it was activated, let off and it was back to go.

 

It might still be some fun, but I don't think you'll see as much advantage with a mild cam like that. A stock or slightly looser than stock fixed pitch setup is pretty hassle free.

Devon

 

Thanks...I am going to get some more info about the history of the tranny and will report back to you...

 

Well, I made a trade with the owner of the switch-pitch. I needed a edelbrock performer intake and he had a new in box intake. He needed a 2004R trans and I had the one he needed so we traded straight accross, even swap. Worked for both of us.
Now regarding the switch pitch he has. He said it's a TH400 modified with what I believe he said to be a switch pitch conv or upgrade by Kenne Bell.
I was in a rush to beat the traffic (which I didn't) and made the parts swap and bailed asap, but told him I wanted to talk more about the transmission later.
I always forget the key questions to ask. I will make a list from your suggestions and let you know what else I find out as I know.
Scott

 

Kenne-Bell was pretty much the pioneer for modified variable pitch transmissions and converters. If you discover it was sold through Poston Enterprises or PAE, I'd pass on it. To many negative issues.

Devon