Is This True? The 6 speed TH400, Introducing the “Switch Pitch ST400”
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- เผยแพร่เมื่อ 30 พ.ค. 2022
- I have a couple hours to get some repairs done, so I pull the BOP Turbo Hydromatic 400 (TH-400) out of the 1985 C20 Suburban and prepare to replace it with a 1967 Switch Pitch Super Turbine (ST-400) out of a Rivvy! More Towing Variability, TWO STALL SPEEDS!
Bruce Roe - Switch Pitch Controller Box Contact Info
BRUCE ROE
5719 EAST SKINNER ROAD,
STILLMAN VLY, IL 61084-9215
email: bcroe@juno.com - ยานยนต์และพาหนะ
Yeah, I can see the welds.
Thanks for posting Bruce Roe's adress and e-mail info. It's good to see that someone is still dedicated to keeping Switch-Pitch technology alive
Valve body is the same between fixed and switch pitch. Different parts are pump, input shaft, and converter. Also need to add a plug with a .040" orifice to the case passage that feeds the stator valve circuit in the switch pitch pump.
Thanks, now I know what I have. I taught mine was just a Caddy Turbo 400. I’ve been trying to sell it as a turbo 400. Now I’ll change the listing.
Thanks for the video. I have a factory switch-pitch TH-425 in my 66 Corvair that has a 455 power plant conversion from an early Toronado in the back seat. The guy who makes the slick aftermarket controller you mention is Bruce Roe. A lot of the GMC motorhome guys use these switch-pitch units as well.
My all original 1965 Olds Delta 88 has the switch pitch setup. The clue was the throttle assembly with two wires coming from it. Trips people up at care shows all the time. Rarely to folks know what it is.
A swp pitch has commonly 2 choices of convertor diameters
Aswp is convertor // input shaft and front clutch // front oil pump // valve body
Small parts are valve body clips / solenoid / oil restrictor plug .// 2 pin electric plug
Cut me a Switch...Thanks Dallas. You've Beaten me with Tech
Very cool!
Unbelievable that Ive been a gearhead sense since 1981 never heard of them
The thing that switches pitch in the torque convertor is the stator. They have a low angle and a high angle. A torque convertor has 3 main parts, the pump section which is in the back side of the convertor housing and is driven by the engine, a turbine which is splined to the input shaft and a stator which is splined to the stator support. I don't know what the extra welds are that you were showing (they are in the pump area of the convertor), but it doesn't hold that stator. It is held by the stator support on the front pump.
That kickdown switch is one of my pet peeves. Always leaking everytime I dealt with one. Then a little while back I saw one that has a healthy dose of silicone to make up for the crappy o ring and I kinda face palmed.
Really love seeing all the BOP stuff. I know it's gonna help me fix or understand something down the line.
Th 400 also used in Australian v8 Holden.. only behind the 308 cu Holden v8
Good info Dallas, I'm secretary learning about GM stuff because of you, thanks alot....
Oh crap… I hope it’s just for knowledge and you don’t get addicted to another brand. It’s like having 2 girlfriends… fun after a few beers but damn is it expensive!
@@mr.roddersneighborhood2740 😆 🤣
I love the ST400 in my 67 GS400. Really cool how it works. Only thing I need to do is fix the throttle linkage microswitch so I have high stall at stoplights.
I put a link in the description so you could contact Bruce Roe, designer of the control box. It will make those switches useless and work so much better.
Check the small micro switch on the carb linkage, this switch is supposed to put trans in hi stall at stoplight idle and to prevent creeping ,it’s position is adjustable enough where you’ll be able to fix problem . The big sliding switch (also on carb linkage) in front of the micro switch ,also switches stall speed,& passing gear & assuming it’s there & connected does not require any adjustment
I had been in touch with Bruce Roe a few years ago about a controller, I ended up selling the car before purchasing the box though. Now that I have the 67 back I will probably order one.
@@audiospanked4787 I had adjusted that switch once before, I might try a small amount of contact cleaner and see if that gets it working again. The kickdown/stall switch that goes to the carb seems to work fine. I'll get high stall in 3rd once I go past 50% throttle and I will get the 2-3 downshift at WOT
That's cool info, I never knew that even existed . Good video
Glad you liked it! I blame squirrels too!
Well that's pretty cool. Take care.
the only problem is there so rare you couldn't wonder to far from home without a spare you can't find parts anywhere I've started to stock pile th475's because i can't get parts anymore it's become almost impossible to get straight cut planets my main parts guy is saying soon the US may run out of 4l60 parts and that's a big chunk of my business.
May I suggest a trans cooler & a B&M shift kit , (I prefer stage 2 on shift kit ) you might prefer stage 1 . Had one set up like that behind a 70 455 the 1-2 shift was unreal in hi stall & still fantastic in low stall , and never burnt the fluid
I acquired a 66 switch pitch 400 awhile back for my collection of 400s
hi SWP was invented as a need to have acceleration with economy . Very large car with 27 inch tires and a 2.5 rear diff gear
Torque converters are black magic to me. I dont know squat about them if I am honest.
👍👍👍👍👍
Thanks Dallas I been wondering about it, can you put that dual pitch torque into a regular turbo 400? If so how . You're one smart cookie . I learn so much watching your videos thanks. 😁👍
Yes you can! But you need all the switch pitch pieces that are in the thumbnail. You can also use the ST300 torque converter that came behind the 6 cylinder 225 Buick and have a High Stall and even higher stall setup!
Noice!
There was a reason they only made these for a few years. I imagine you’ll end up being sorry you made this switch.
Also, the Buick Dyna-flo was in fact not a 2-speed, technically. It did have a variable torque converter but it was not the same as the ST300 or ST400. They had a “low range” planetary inside the torque converter that only came into play when “L” was selected on the gear shift. It was only intended for high load starts, such as pulling off on a hill with a trailer, etc. OR when descending a steep grade. Manually shifting from “L” into “D” under part or full throttle acceleration was discouraged by Buick and was a sure-fire way to tear up your Dyna-flo.
In normal operation, a Dyna-flo basically operated as a single forward speed trans with a variable stall converter - almost like a centrifugal clutch. They were boring and terribly inefficient.
The reason they only made them for a few years was GM picked up the entire ST400 and called it the TH400. The switch pitch was unnecessary overhead and was not needed in some cases. Especially later when 500ft/lbs of torque at 2800rpm became a thing.
You know not what your talking about
I have a 66 Buick Riviera GS with a built B&M ST400 S.P. trans
Im using a nitrous full throttle switch to activate it
I've done lockup 727s and A518/45RH transmissions in full sizs Cherokees, but that switch-pitch might be the thing to do in this 79 I'm looking at. Does anyone remember what the two stall speeds were?
Like everything, it depends on the converter. If it is a full size car converter it’s like 1200/2200 behind a big block. if you use the ST300 converter for a small block but put it behind a big block it would be 1500/2500ish, if you find a 225 v6 converter and put it behind a big block it would be more like a 2000/3000.
64-67 BOP th 400 had switch pitch in many cars.
You need front pump, forward clutch/input shaft and converter.
It give higher stall speed so big engines with more cam used it so the would idle at stop light.
It also had 1.96-1 torque multiplication in high stall.
He is wrong rhe case isnt heavier its a BOPC case.
Be damned Dallas I never knew that one ever existed..very interesting
interesting
Do you have the info for the guy in Illinois? I would like to get me one of those control boxes for the variable pitch.
I like this switch pitch thing. Wonder why that technology didn't become commonplace.
I think it was a carry over from the 2 speed automatic dynaflow days and with the addition of the third gear in the transmission, it was likely not needed and deemed too expensive for little gain. Ya know... bean counters.
@@mr.roddersneighborhood2740 The cars were heavy and the motors were weak is why they used the V.P., variable pitch converter.
Personally I blame squirrels
Don't throw 🥝ZasBerries at them, Uncle squirrel 🐿️
@@deanstevenson6527 lol
How strong can a switch pitch convertor be made with a Turbo 400? I have a TT LS that will make about 1700 HP.
It’s similar to any other TH400 converter with exception of a movable stator. I’m assuming you can do almost the same stuff to a Switch Pitch converter as you can any other TH400 converter with the added benefits of an adjustable on the fly stall speed.
@@mr.roddersneighborhood2740 Great to know. Thank You.
So thinking backwards can I put a 400 lockup converter into a switch pitch th425?
This ST400 is not a lockup converter, it has two different stall speeds on a switch. I’m sure since the TH425 is very much a TH400, I’d bet it can be done if the pump and input shaft are interchangeable.
@@mr.roddersneighborhood2740 I’m about to order a switch pitch for a project and would love to be able to lock this thing up. It just dawned on me that maybe, since they use the same converter switch pitch or not.
I have seen a th400 from72 that had the two prongs
Then it was not original or the plug had been changed. Switch Pitches ended in 1967, no doubt about it.
@@mr.roddersneighborhood2740 I thought that the input shafts were different and that's how you can tell
@@66mike they are different, but without having one side by side, there is little you could tell by looking at it. There is not some simple giveaway other than the plug on the side or the welded converter. You would need to pull the pan or the pump to see.
That is correct but not related to switch pitch. It is related to smog or economy systems in 70s.
Can you have this on any gm ??
Buick and Cadillac mainly but was available as an option on Olds and Pontiacs.
all the info i can find is the 2 speed trans maybe MAYBE had diffrent stall speeds than the st 400 so if you swap them you can have off the top my head a 1200 stall or a 2800 stall you can make the st 400 high stall being a so called gear and low stall being another so called gear kind of a gimmick thats all the info i have found update me if you find more lol i have 3 67 riviera one 66 gs now bear with me hear super wild cat that 425 twin carb engine was taken out for some skylark guy wanted 15k for the engine 1200 for the minty ish roller only a hand full of super wildcat in 66 to my understanding would make my car valuable if i had bought that engine instead found a 401 nail head fort it lame