Kickdown - really needed?

Hello folks,

transmission builder is finishing my 904 and I told him that I wasn't planning to use the kickdown. He was very upset and said it´s mandatory to use it.

Sorry my ignorance but is this true? Wha would be the issues of not using it?

Car will be street/strip...


Thanks,

If you are not using a manual valve body then yes, it is mandatory otherwise front clutch failure will soon follow.

You need to understand that kickdown is an incorrect name for the linkage you are talking about . It is actually throttle pressure linkage and that tells you why it's necessary. It actuates a valve in the valve body that adds pressure to the system as you increase power to keep the clutches and bands applied rather then slipping and burning up. With out that linkage the trans will fail very quickly unless you have a manual valve body in it.

Will use Transgo TF2 shift kit...

TF2 Don’t matter, you will be pulling it out after 200 miles or less. You have been warned.

you need it, if you don't have it, you'll blow your trans. if you don't want to use it, you need a manual valve body

Shift kit DOES NOT replace the linkage.

You don't have to use the TV linkage. But when the trans takes a dump prematurely, you'll wish you had.

Ha ha, exactly.

The TF-2 kit gets good reviews & I think with an adjusted correctly kickdown & the largest cooler that will fit in front of the rad that you will be good to go.

FIND a new Trans guy ...

FWIW, I ran my car years ago without the linkage; it was not installed when I took ownership of the car. Best guess, the rebuild had maybe 3-4000 miles on it. I built another motor and had the tranny re-freshed at that time. My low/reverse band was burnt up. There were a few other small parts that were bad too but, it's been so long, I can't remember.

At the time, the tranny was not doing anything stupid, I was just going to put some more power to it and had it out so; I thought it was an opportune time to have it gone through.

If I can remember right, I put a couple hundred miles on the re-build without the linkage too. At that time, I learned of the importance of the linkage. The car was my dad's and my brother still owned his house so; I pretty much knew where all that stuff was. I went to my brother's house, located all the parts other than the bell crank (I bought that used of E-bay) and I installed it all.

I have probably 6000 miles on the tranny without issue.

Why? The transmission guy was right. Do you abandon someone that gives you correct advice?

If you want a more exact throttle pressure linkage without the rods use the Bouchillion cable kit along with their throttle cable bracket. I have used them multiple times over the years with great success
If you want to ditch the linkage you may as well zip tie the pressure wide open and go

Well FRANKENfurter.... why don’t you delete that KD on yurr FRANKENcharger and seabhowvthatvwerks ferr u !!

Doc F, don't be giving wrong advise about the KD linkage. It is necessary unless it's a full manual automatic.

Doc is backwards again. The Trans guy said it was mandatory. I agreed. Where is the confusion?

I picked up on where Doc was going with it.
He was being sarcastic about why the OP would be questioning his trans guy's intelligence.

Ok, so looks like the concense it that I need it.. I just want to find the best way to do it as I don't have the linkages.. maybe cable is the easier way to go...


There´s some old chrysler video here...

1971 Master Technician Service Conference
https://youtu.be/KsfI9cFFPpg

To BullBob and the rest ! ..., no sarcasm on my part !! ... jsta total BRAIN FADE on my part ! I misread it..... BIG TIME.

BUTTT .. You CAN drive without KD linkage if you tie the lever back about a third of the way ..., if you drive it EZ. Do thatt - then put in a WANTED AD back in the swap meet section here and get the right OEM parts. I have never used a cable set up .... I’ve heard mixed reports about that setup....

FRANKENfurter ... I’ll EAT CAKE on this one !

The cable does work okay, but I very much prefer the linkage. The linkage takes some original Mopar pieces and some fabrication skills to put together. The cable only takes some money.

And yes, there must be some way for the throttle position to be relayed to the transmission. It is absolutely essential to the proper operation and survival of the transmission.

What motor is in front of this 904. I would imagine it is a small block and the parts will be available for a reasonable price. Try National Moparts or others that would have this parts and deal with used parts if you can not find the kick down locally.

https://nationalmoparts.com/

there's the Lokar and the Bouchillin (sp) aftermarket kickdown cable setups & there was one of the two iirc that got a lot of bad reviews but I will defer to others on this/which (one) is recommended OR if a different route is recommended. In the meantime I would tie it halfway back & see where that puts your shift points & go from there.

If you want to see why it's needed, hook up a pressure gauge to the mainline pressure, start the car and move the kickdown lever while watching the gauge. The more pressure the tighter the clutches are held. The transmission shifts between two pressures throttle pressure and governor pressure. the more throttle pressure, the more mph you need to develop the governor pressure to make the shift valve move. throttle pressure is also use to provide load to the valve body, as throttle pressure increases so does the mainline pressure. Higher the load the more line pressure you need.

RR, it's the lokar setup that gets a mixed review. myself, i don't like them one bit. i have played with them over the years, and have removed many because they are a GM [i think ] design cobbled into a mopar option.
my observations based on my experience. the brackets are cheesy, bending very easy, hard to adjust correctly in the factory ratio needed for the transmission to operate correctly, and a cheap, hardware store type of bicycle cable that stretches very easy, just to name a few.
i don't like them, and the factory setup is well worth the cost to track down and install.
just my opinion, but others i believe, will agree.

Cheers.
I have the Bouchillon cable setup in the Charger...10,000 miles on it without troubles. Lokar? Uhhh, I know of some that have had troubles with those.

John Kunkle laid out the problem with the Lokar kit years ago.
Not all Chrysler transmissions use the same lever for throttle pressure.
Before the Bouchillion you used to have to play with the lokar because of lit. The Bouchillion kit uses 90% of Chrysler parts and the guesswork is done

Would you post a link? Have been using LoKar for several years, but NOT totally happy with it. Did not know about Bouchillion? I don't get out a lot

Here's my standard Lokar rant:

The problem with the Lokar is that it's generic even when advertised to fit a Mopar because of the different lengths of the transmission lever.

If the generic Lokar instructions are followed and the cable adjusted so that the trans lever is full back at carb WOT you can see (simple math) that the first 3/4" to 1 1/2" of the lever travel is already used up at idle and there's no spring to pull the lever forward.

It's not unusual to see these Lokar installations have light throttle 1-2 shifts at 25+ mph and 2-3 at 40+ mph or even higher and, possibly, no 2-3 upshift at all. If the cable is adjusted for correct light throttle shift points there is insufficient TP at WOT and no forced downshifts. Potential damage.

So, as I've repeatedly ranted, the Lokar works OK if the installer ignores the Lokar adjustment procedure and knows to match the total travel of the cable attach points and installs a spring.

You need to measure the full travel of the carb lever where the cable attaches and then measure the full travel of the transmission lever where the cable attaches; it usually won't be the same so you need to drill a new hole in the transmission lever so that the full travel of both levers is the same. Also, there should be a spring pulling the transmission lever forward.

It isn't necessary for the trans lever to be full back at WOT but be sure that WOT under the hood is the same as WOT at the pedal...misadjusted throttle linkage will prevent the carb from going wide open when the pedal is matted and that, in turn, will prevent the trans lever from going back enough to provide kickdown.

Remove the cable from the carb and measure how far the hole in the throttle lever moves from idle to WOT. Then measure how far the hole in the trans lever moves from full forward to full back. The movement of the trans lever will likely be more than the carb lever so find the spot on the trans lever that matches the travel of the carb lever and drill there.

It's unlikely that the trans lever will return to the full forward position without a spring assist.

John, we want pedal WOT to deliver carb WOT & carb WOT to move the trans lever ALL the way back or ALMOST all the way back? (& drill hole in trans lever for the right amt of travel) & a return spring to move the whole shebang back forward when you let off the pedal.

Bouchillon Performance Engineering

Yes, simplified version of my rant. Original factory setup did not place the trans lever full back at WOT; in some cases, doing so will prevent a 2-3 upshift at WOT.

thanks John & sometimes it's good to rant. & for "almost" all the way back is there something to monitor to fine tune that? (shift RPM or something else) or is it a non issue?

"shebang"

Blast from my mis-spent youth on the Western Slope of CO with that one RR. I get some strange looks when people here me use that the 1st time! Haven't heard anyone but me and the old man use that in quite some time.

Not even going to feel bad about mucking up the thread with this, made me smile at the end of a tough day!

that's good to hear & I'll be 68 next month & you ain't mucking anything up as we needed a light hearted turn on this.

I like Lokar cables, but I figured out on my own that they are not "plug and play".

I also figured out the hard way in 1980 why you don't run a 904 or 727 without the kd linkage. The link fell out of the front band, the drum caught it and spun it, and ruined the drum. Lesson learned.

I went with the Lokar cable many years ago, as it seemed to be the only option at the time. Worked OK as was, cable stretch was an issue as has been mentioned.

I've since added the arm and spring return setup from Bouchillon and I haven't had to adjust for a stretched cable for several years.

I have an older (I believe) AndyF throttle setup that has a couple of fwd facing holes below the cable platform, one of which lines up perfectly to attache the cable directly to the lever on my QFT carb.

Once I installed the return spring setup, it was very easy to adjust for travel as has been described in this thread.+

I have slightly less $$$ in the whole shebang than the Bouchillon setup costs now, though I'm sure the Lokar setup has increased in price since I bought it.

Thanks guys for all the shared information. Will be very helpful!

Any of you knows aproximately the lenght of the Lokar/Bouchillon cable? As I have to import it, so due to import taxes it would arrive here very $$$ so I'm thinking in doing it myself with some motorcycle throtle cable or something like that. Reading your information looks like it´s not rocket science.

Also, any electrical conversion every tried? I already have the position of TPS on my EFI (0V closed - 5V WOT).. so would be very easy to implement If I have the correct device to turn the valve (stepper, etc..)...

Can't answer as the the electrical, but the cable should be fairly easy to rig up. If the engine and trans are out of the car and bolted together, it would be easy to mock up, in the car, less so.

Take a look here, and you'll see their approach.

http://www.lokar.com/assets/instructions/INS0046-ChryslerKickdown.pdf

Looks like mostly off the shelf stuff.

I doubt you'd need more than 40" of cable and I'd bet a motorcycle or even a good bicycle shop could swadge the housing ends for you, once you have the length.

You can rig up a return spring and cable housing attachments that bolt to the shifter linkage bosses on the trans, or a tab that goes under one of the tail housing bolts for the cable housing. Drill a hole in the kickdown lever for the return spring to attach to. Cable housing retention at the throttle end will take a little work to sort out.

The Bouchillon setup is beefier, but not so off the shelf.

I bought my 77 D100 pickup 7 years ago. It never shifted right when I first got it, so I started trying to track down the problem. Turns out that the dweeb I got it from just threw a bunch of parts at it. It had small block brackets and God only knows what the other parts were from. Long story short, I needed to drive the truck, so I bought a cheap eBay copy of the Lokar kit. I put a spring on the lever at the trans and the carb end of the cable and with a bit of adjustment, it's worked fine every since. It was a pretty easy and basic fix to make it work and I have used the same set up on several other vehicles over the past few years. If you use the cable set up, be prepared and pay attention to the travel and set it accordingly as stated by others.

Reverse pattern manual valve bodies in everything I own. Daily driven. Never missed auto function for a second.

The RMVB is fun with the correct shifter. Fond memories of 440 Challenger with Cheetah VB and B&M Mega shifter. Whats the other deleted function- engine braking? That was eliminated too. Pure enjoyment.

Good discussion here. A few years back a local guy had a 62 Plymouth with a poly in it and a cast iron 2 X 4 intake manifold with Eddy's on it (which he was convinced were Weber carbs). The carbs were hooked together and opened simultaneously as you drove.

He wanted someone to change out the intake setup to something a bit for street friendly. To his credit, he realized the setup was pretty impractical for a family cruising car. He didn't care what went back on the car, he just wanted it to be more manageable.

When I looked at the car I told him he needed kickdown linkage too as it was gone. He replied "but the car shifts so smooth you can't even feel it". I've no idea how long it had been operating like that but tried to explain things to him. I guess he thought I was trying to fill him full of BS.

Anyway, I did the intake conversion for him and installed 65 vintage kick down linkage I had sitting around. I just put an original poly 2 barrel setup on it, fresh carb, painted things up, etc. Played with adjustments a bit. The car drove and shifted great. Completely different car. Responsive, crisp shifts, immediate throttle response.

When he came to get it, I had him take it for a test drive before we settled up. He came back just grinning. "Can't believe how great it runs. It actually seems faster now." He was so happy he gave me a bunch of extra 62 parts he'd originally gotten with the car. I got the dual quad setup as payment for the job. We were both happy with the outcome.

Initially I was tempted to just let him drive it till the transmission gave up, and then buy the car from him as I really liked it. My conscience would have bothered me.

It definetly needs to be correct if you don't want to have the trans clutches get worn out very fast. I also prefer to run reverse manual valve bodies in my muscle cars as I love to shift it when I want it to shift and I do race my car sometimes. I had a friend a few years back bring his 340 Challenger to me that he said would not shift right. And he was right as it had a Holley carb on it and linkage to the trans throttle pressure for who knows what. Once I got it set to shift ok the car was way off from full throttle as it was lucky to have 3/4 throttle. But the trans linkage was all messed up with a bunch of parts from different cars. I told him I need to get the right throttle pressure rods and linkage or get a good aftermarket setup to work right. He took it anyway that day as I set it to have good upshifts and shifted fine but no full throttle. Ron