Nearly every automatic transmission has some kind of kick down apparatus and they are all different. This switch has a wire going down to the transmission to a detent solenoid inside the transmission that caused the transmission to drop down a gear below 70 mph.
We took off the QJet carb almost immediately after we bought the car, replacing it with a Holley carb. You can skip down to wiring part of this article. There you have several choices. The instructions say you should reuse the TH kickdown cable bracket.
TH400 without electric kickdown
We found a TH kickdown bracket for a small block Chevy that was lying in our spare parts bin. Assemble the switch, spring, cable, and carb linkage as shown in the picture. Wiring the switch is really simple. One wire needs to be hot when the ignition is in the on position. We used this wire with a plug that was just dangling there unused. We even had a wire with the matching plug in our wiring supply box that plugged right in. The other end of that wire is connected to one terminal on the switch.
Our car still had the original orange wire that was amazingly not melted to the exhaust pipe, so we reused it. If you still have the original downshift switch on your engine like this one, you only need to wire up two of these terminals. You want the wire from an ignition hot source connected to the IGN terminal. The SOL terminal needs the wire which goes to the vertical spade on the side of the transmission. See, there are advantages of keeping your car stock. Turn the ignition to the on position and pull open the throttle.
The switch activates as soon as the pole is starts to pull out of the switch. The cable runs through the cable stop at the end of spring, and continues inside of the spring.
Just loosen the small screw in the cable stop to move the cable in or out to the desired position. Use a test light to see that switch is activating at the desired throttle position. At this point, we test drove the car check to see if our switch worked. AT this point, we decided to seek advice from someone who has more knowledge than us in this area. We stopped by Culver City Transmission to see the owner, Rick, and asked his opinion.
You mean open up the transmission in the car, we asked? Many of us bang shifters are ok tearing apart engines, rebuilding suspensions, welding this and that; but when it comes to messing around inside an automatic transmission, we turn into jelly.Aug 10, 1.
Messages: Likes Received: 0. Aug 10, 2. Messages: 46 Likes Received: 0. You sound like your in the same boat as me. Are you planning to do the work yourself? I think mine is going to end up at the shop. I'm a little scared of tranny work. Aug 10, 3. Messages: 11, Likes Received: 4. You need a switch to provide power to that electrical connector- either one attached to the gas pedal or one attached to the throttle cable linkage at the carb.
Swap Meet here, e vil bay, GM dealer. As you have an 80Z- look at how your cowl hood solenoid is activated- by a switch on the gas pedal- same thing has been used in some applications for a TH kickdown.
Aug 10, 4. That's what I figured. What was the stock setup on the 80Z?
Kickdown help with my TH400 and 80Z
Was it the pedal throttle switch or carb throttle cable? I understand how the cowl hood setup works, but haven't seen anything for sale that sounded similar. I planned on hooking up the cable myself, but leaving all of the other trans work to the pros.
I don't have a garage anyway, so Also, does anyone know much I should be looking at to have the trans seals replaced? I don't want to get ripped off. I took it to Cottman for a free inspection and I knew the pan was leaking at least previous owner was an idiot and put some RTV or something with the gasket to seal the pan.
Plus whatever the resealing costs. Sounds too high. Aug 11, 5. Messages: 1, Likes Received: 0. Remember, you need to remove the transmission from the car to do the front seal.
This takes time. There also a manual shaft seal, dipstick tube seal, kickdown connector seal, governer cover seal, a modulator seal, two speedometer seals, and a tailshaft seal. Sounds fine to me if you're having ALL the seals replaced. The kickdown switch can be bought from your local GM dealer.
It mounts right on the gas pedal bracket. All you need to do is supply some hardware, like a sheet metal screw, some wire, and some connectors. The shift calibration takes a bit more work and description of the problem. Bear in mind, if you have a lower gear ratio 4.Forum Rules. Now through Dec 31st, Recent Threads Anyone else stuck at home?
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Fender Flares Oil change question. UConnect apps and more. Wrangler TJ No More Reader Rides. Thread: TH or Torqueflite Join Date Feb Posts Join Date Aug Posts 2, I still have a TH with Jeep bolt pattern for sale. It will need to be built. If you are going to use a Dana then you will need to get a Novak adapter for it. You have to upgrade the crap out of a to get it as strong as the is stock. I have been dogging the other one that's in my Jeep for several years with no troubles.
It's sitting behind a and pushing a 60 and 14 bolt with 39" Boggers. Safety yellow and Handicap blue CJ with 5. I have a t approx mi going strong. The TH is stronger. The Torqueflite is by no means a weakling though.
America: the land of the free, because of the brave. Please support our troops. Join Date Jul Posts 1, The TH is probably first choice, the TF a close second. If you get themake sure you get a kit to match the carb witht he transmission. The TV set up is critical.
Dana 44 rear disc swap The TH has an electric kickdown so no need for carb changes. Wire up a kickdown if you want it and you're done. I shift mine manually anyhow so I never wired a kickdown. Bye the way, it compression brakes like mad with the 3. I don't even have to touch the brakes going downhill.
You can do away with the factory solid rod type kickdown with a cable kit from Lokar. You could also convert the valvebody to full manual operation with the race version of the Transgo brand reprogramming kit and eliminate the need for the kickdown, but the automatic function will be gone and you will have to manually shift up and down ALL the time.FYI — some of the links below may be affiliate links, which means at no cost to you, we will earn commission if you click through and make a purchase.
This helps us keep the lights on and we appreciate your support! Read more to see how with lots of pics! I want to clear up some confusion here. I documented what I learned and hope to provide some clarity for you here!
FYI — some of the links below are affiliate links, which means at no cost to you, we will earn commission if you click through and make a purchase. If you get a 4. The reason you need this is because the LS motors have a crank that is. The dished style of the flex plate makes for the same bolt pattern, but the Hughes flexplate adapter spaces the crank out.
You will also need to have a carbide burr in order to elongate the flywheel holes for the slightly larger bolt pattern on the TH torque converter.
Something like this:. The spacer is needed because the snout on the center of the torque converter is what centers it in the crankshaft.
Warningmake sure you use Locktite on the 6 flexplate bolts and follow proper torque sequence alternating side to side. You can find the LS adapter on Amazon for pretty cheap considering how easy it is to install and that no other additional parts are needed. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. Leave a comment Cancel reply Your email address will not be published. Sorry, your blog cannot share posts by email.Login or Sign Up.
Previous 1 2 template Next. Posts Latest Activity. Page of 2. Filtered by:. Scott Liggett. October 30th,PM. I want to rehook up the downshift switch, or passing gear switch, on the Caprice's TH It's basically a push button switch that is activated by the carb linkage opening to full throttle. There are two wires that connect to the trans. An orange and a black, I think. The plug and switch have four terminals, but for the life of me I can't figure out where the other two wires are, if there are any.
And, which of the terminals the two wires from the trans go. The wires came out of the terminal connector and I don't know how where they go. Here's a pic of the switch with it's terminal markers. BS'er formally known as Rebeldryver Resident Instigator sigpic. Tags: None.
thm 400 kick down ?
What exactly does it do??? The info I'm finding is quite confusing. Some say it works without being hooked up, some say it won't. Some say it changes line pressure at WOT along with forced kick down, Some say it don't. Because of the line pressure, some want it on a manually controlled toggle These guys discuss quite feverishly to defend their positions.
Last edited: Jun 23, I have a small homebrewed Turbo kickdown switch. Deuce RoadsterJun 23, The transmission will kick down if the electric kickdown wire is not installed Let's see what Chevy has to say about it. Notice the "boost" end of the pressure regulator valve, which is getting "yellow" oil because of the detent.
I have a caddy in my car and never would get to the kickdown when accelerating unless i really was getting serious or when i am running at the track. Thanks squirrel.
I have installed for customers a Nitrous switch from Edelbrock to operate Chevy kickdowns. Works perfect. The difference with or without it is night and day. Since I am a Mopar guy despite working on all makes for others I would suggest you dont hook it up and listen instead to the experts who have never hooked up nothin. That way if I or my Mopar or Ford friends meet you at part throttle on the street we can fry your butt with ease thus saving us fuel and time.
DolmetschJun 25, I have been manually shifting up and down my th, I do not have the electronic kick down hooked up. My trans has a mind of its own, I can hold first, shift to Second at say rpms and it may shift then or maybe at and it verys, it will only shift when i tell it to at lower rpms, any thought why this might be? I have shifted at manually and it not shift till rpms.THM-400 Transmission - kick down solenoid failure.
Godspeed MrC. Usually a stock th will shift at around if the kickdown is working.I recently bought a T-bucket with a Chevy and TH tranny. Does this trans need a kickdown cable or TV cable? The old TH didn't have one, and it all ran fine, but I don't want to destroy a new transmission!
Let's take it from the top: Many old-school automatic transmissions use both a governor and a vacuum modulator to help regulate automatic shift timing. The governor works off of vehicle speed and engine rpm. As vehicle speed increases, springs and weights inside the governor are thrown outward, causing the governor to increase the transmission's internal hydraulic pressure.
Higher pressures will cause the trans to shift automatically to a higher gear. Think of this as somewhat analogous to a distributor's centrifugal advance mechanism. But there are some situations where engine vacuum engine load may not correlate directly to speed and rpm. For example, climbing a steep hill puts the engine under load, resulting in a low-vacuum condition—even though initial vehicle speed at the base of the hill may be relatively high.
That's where the vacuum modulator comes in: A rubber diaphragm located inside the modulator housing on the side of the transmission case is referenced to engine vacuum. Diaphragm movement induced by changes in engine vacuum actuates a lever or spring that acts on an internal hydraulic throttle valve to change the transmission's pressure.
In other words, a vacuum modulator "modulates" the transmission's shift points to engine load rather than just plain vehicle speed. In the case of our hillclimber, low vacuum causes the modulator diaphragm and linkage to push the modulator valve further into the trans, delaying any upshift to help the car accelerate better up the hill. Here the rough analogy would be an ignition distributor's vacuum advance system: Higher vacuum equates to more distributor vacuum advance in the case of the engine and higher transmission hydraulic pressure with consequent higher gear selection in the case of the transmission.
These "vacuum modulator-assisted" transmissions will employ a kickdown cable or an electric switch, in the TH's case that serves only to "kick-down" the trans into a lower gear for passing when vacuum is otherwise high.
At sudden wide-open throttle WOT under highway cruise conditions, the cable, lever, or switch actuates a kickdown valve in the trans.
Because this is a full-throttle-actuated function only, there's no fine adjustment required. In fact, if you don't mind downshifting manually with the shift lever when passing, there's really no need for a functional kickdown cable or switch at all.
Even manual downshifting to obtain passing gear may not be needed in the ultralightweight T-bucket's case because it has so little inertia. Do not confuse a simple kickdown cable with the more sophisticated throttle-valve TV cable used on transmissions that don't have a vacuum modulator, such as the GM R4 and R and Ford AOD. In this type of trans, a TV cable directly actuates the throttle valve to regulate part-throttle downshifts, detent downshifts, line pressure, and in conjunction with a still-present governor even upshift points.
TV cables and linkage have sophisticated adjustment procedures. On transmissions designed around a TV cable, its presence is mandatory. You must install a true TV cable with the correct throttle-lever pivot geometry and then adjust it properly or you will burn up the trans! Marlan Davis Writer, Photographer. Share on Facebook Share on Twitter.