Kickdown confession

[Banzaiii67]

I kinda feel like an idiot.. Adjusted my Lokar Kickdown Cable following the instruction from this article http://www.hotrod.com/articles/the-lowdown-on-stock-torqueflite-kick-down-linkage/

Per Article

As the kick-down linkage/cable pushes the kick-down lever rearward, it increases line pressure inside the trans and initiates a downshift. “If you adjust the cable so the lever is at the front of its travel range at idle, the line pressure will not increase properly as the throttle increases,” Jason Muckala of Motech Performance explains. “This makes the trans shift too early, and it can cause the clutches to slip and destroy the transmission. I’ve seen people install springs to hold the lever forward, but it’s not supposed to stay in that position at idle.” This photo shows the lever full forward; in this portion of the lever’s arc you can feel no pushback from the lever, an indication that no increase in line pressure is occurring.

Somewhere in this range of the lever’s arc, you can feel a slight resistance from the lever’s internal spring. This is where the line pressure begins to rise, ultimately causing a downshift. Properly dialing in the lever’s range of motion is critical to shift performance and transmission longevity. Says Jason: “For the first half of its travel range, there is very little resistance and the lever does nothing. At the halfway point, you can feel where it starts to hit the valve inside the trans, and that’s the position the lever must be in at idle.”


I ended up tighten the Lokar cable A LOT to get it the lever where the article suggested.. I'm pretty concerned about my transmission health now though. Although after the changes driving in Drive, it a whole different beast. 1st gear now shifts at 4500 Rpms, 2 gear at 5700rpms at wot, and now it will Kickdown properly from 3rd to 2nd.

The only thing a bit annoying is under part throttle to get it to shift from 2nd to 3rd I have let off the pedal and it will shift otherwise it stay in 2nd until about 4000 rpms.

Shift quality is good and firm but not jarring and I don't feel any slipping at all. I sure hope I'm in the clear. Trans pan will get dropped this week, keeping my fingers crossed.

 

[Mike67]

I would suggest using Lokars instructions...I followed them when I did my wife's car using the pressure gauge and test port...it was tedious and finicky to say the least..but I eventually got it to read correctly and it shifts great now.
The return spring that is on the cable closest to the tranny would not push it forward completely so I did have to add a helper spring...

 

[AR67GTX]

I'm resurrecting this thread as I have a related question. I adjust my 727 linkage according to my 67 shop manual by putting a spring on the transmission kick down lever to hold it forward while I adjust the intermediate rod and then the upper rod. But there is a lot of free play in that transmission lever and when I remove the 3/16 inch drill bit out of the bracket holes and remove the spring - it will move the transmission lever to the rear quite a bit before it finds resistance. So if I adjust the upper rod at closed throttle with the spring temporarily holding the transmission lever forward - when the spring is removed to drive it - a lot of throttle is needed to move the lower transmission rod to where it starts to meet pressure (and I assume to increase line pressure).

So - in adjusting the upper rod with the transmission lever held forward - is it better to adjust the slotted rod with a closed throttle - or adjust the slotted rod at WOT??

FWIW the internal kickdown rod on my transmission came un-hooked inside about 5 years ago and I pulled the pan, hooked it back up and adjusted it as best I could by the 67 manual. Possibly I didn't get it quite right. But I do get kickdown at full throttle. I'm planning to pull the trans this winter and go through it - just trying to experiment a little with it right now.

 

[miller]

So - in adjusting the upper rod with the transmission lever held forward - is it better to adjust the slotted rod with a closed throttle - or adjust the slotted rod at WOT??

It's been quite awhile since I've fooled with the 'slotted rod' type linkage, so I'll just put it like this...
All in all, regardless of what kind of kick-down linkage, or cable, all winds up giving that lever on the trans what it wants. Of course, the pressure/kick-down (inside the pan) MUST be adjusted right first. Hell, it's only a measurement for the stop, that limits the travel in there.
No matter how you go about adjusting the linkage, final thing is, at WOT, that trans lever needs to be almost fully towards the rear...or full throttle pressure. I say almost, because it needs to be close, but not binding, that interferes with full carb throttle movement.
There are different length levers for the trans, so you need the right one.

Normal for no pressure at idle, the linkage in free play. The gauge (drill bit size) the book tells you to use on the slotted type linkage just gives an adjustment, so at WOT, the trans lever is not bottomed out, or binding.

 

[AR67GTX]

Miller, I went out to check and holding my carb throttle at WOT and pushing the transmission linkage as far as it will go - I have about 1/2 inch of slot remaining behind the carb pin. I've read on here from someone that about 1/8 inch slot showing is a what should be targeted for. So, I think I'll lengthen the upper linkage to where I have about 1/8 inch room from bottoming out - that will be a pretty big adjustment. Sound OK?

This is an Edelbrock 800 carb with Mopar adaptor - think I'll measure the distance from the throttle shaft centerline to the linkage pin and compare it to the old Carter AVS I have. Possibly the Edelbrock adaptor is closer to the throttle shaft and doesn't move as far rearward as the throttle is opened.

 

[Cranky]

One way to solve all of this is to throw in a 4 speed!

 

[AR67GTX]

One way to solve all of this is to throw in a 4 speed!

I've thought about that - but since it's a full power, factory air car I decided the 727 makes sense. Do you have any opinion of the throttle/kick down adjustment?

 

[miller]

So, I think I'll lengthen the upper linkage to where I have about 1/8 inch room from bottoming out - that will be a pretty big adjustment. Sound OK?

1/8" sounds better. Book will give the prefered gauge distance, though that's using stock carb and throttle arm.
This will only hurt ONCE. You should check the swing range for both the throttle arm, and that slot linkage. You want to be sure, you have free swing range (no binding) both at idle, and WOT. Heck, this is so hard...I can't stand it!
Do that check with both springs off, so you have free movement. If it's good, the linkage parts you have will work. Need to add, at idle position, the kick-down needs 'free play', no tension on the linkage. Normal is no tension from idle, for around 1/2" movement.
Once adjusted, test drive. Remember, if your shift points are off a little, re-adjust the slot gap, but only a half turn at a time, until you get what you want.

 

[Cranky]

It can be a pain in the butt to get things right especially when you are dealing with aftermarket or non stock stuff. Also, there are so many combinations of rods from all the different models and years. Do you have the original linkage for your car? I've mixed linkage and have even modified linkage rods and bell crank pivots to work. The kickdown lever on the trans needs to move when the throttle moves and not end up all the way back before the throttle is wide open. Like miller mentioned, it's not easy to get it right....and even harder to try and explain it lol.

 

[AR67GTX]

I'm not sure if all my linkage is vintage 67 or not. The motor was replaced with as far as I can determine, a complete 68 440HP from exhaust manifolds to intake. I even found GTX scribbled on it somewhere so it may have been salvaged out of a 68 GTX. The transmission is out of another car also. So I'm not sure if the linkage is all original or came from a 68.

The transmission lever appears to have a lot of free play at the forward part of the travel. I doubt it meets any resistance until the throttle has been opened quite a bit. So I think I will try to take some of that out by adjusting the slotted rod with the throttle wide open (leave 1/8 inch extra space on the slot to avoid bottoming) and see what happens.

Thanks

 

[miller]

The transmission lever appears to have a lot of free play at the forward part of the travel. I doubt it meets any resistance until the throttle has been opened quite a bit. So I think I will try to take some of that out by adjusting the slotted rod with the throttle wide open (leave 1/8 inch extra space on the slot to avoid bottoming) and see what happens.

No!
Adjusting those things...really just takes a small bit of understanding what does what.
Bottom line is this...the movement of the throttle pressure/kick-down valve, located in the trans shift body. That is all what it's about. That valve simply moves via the lever at the trans, that also has a travel limit 'stop' bolt, and a measured distance. Whew!
The measured distance I'm talking about, is what gives the 'free' movement on the lever, when it's moved forward. Okay...toss in the lever itself...there's a few different lengths, for various applications (carb, etc, blah, blah.)
That valve, at WOT gets moved to it's full pressure position (less the needed clearance, simply to keep from binding), all through the allowed swing, both levers allow. That's both the trans lever, and carb lever...they work together!
It's a matter of getting the trans lever, to carb, via the linkage, to get the full swing on the trans lever.
If you back off the adjustment too much, and pull the valve out of full pressure, you take the usual risk...not enough pressure=burned clutches.

 

[AR67GTX]

I think I'm understand this OK. I had to go in a few years ago and fix the throttle valve lever inside the transmission. From memory there was a lock nut or something that backed off and the linkage somehow came un-hooked. I adjusted it according to my 67 manual - but it's not a 67 trans from memory so that could be a problem. The transmission throttle lever has a lot of free-play in the forward position before it meets resistance inside the transmission.

Anyway - I adjusted it again this morning. The lower rod and intermediate rod are adjusted exactly as stated in the service manual - with the transmission lever held all the way forward by a strong spring. The upper rod - I adjusted with the throttle held wide open and the transmission lever pushed all the way to the rear - with 1/4 inch additional slot clearance to avoid bottoming the transmission valve.

Now - for information - when I unhook the transmission linkage spring (not throttle spring) and let the weight of the linkage fall and push the free play out of the transmission valve - I have 7/8 inches of slot behind the carb pin. That's how much forward free play is still left in the transmission arm after this adjustment.

Roads are still a bit wet from rain yesterday but I'll test drive after they dry.

No!
Adjusting those things...really just takes a small bit of understanding what does what.
Bottom line is this...the movement of the throttle pressure/kick-down valve, located in the trans shift body. That is all what it's about. That valve simply moves via the lever at the trans, that also has a travel limit 'stop' bolt, and a measured distance. Whew!
The measured distance I'm talking about, is what gives the 'free' movement on the lever, when it's moved forward. Okay...toss in the lever itself...there's a few different lengths, for various applications (carb, etc, blah, blah.)
That valve, at WOT gets moved to it's full pressure position (less the needed clearance, simply to keep from binding), all through the allowed swing, both levers allow. That's both the trans lever, and carb lever...they work together!
It's a matter of getting the trans lever, to carb, via the linkage, to get the full swing on the trans lever.
If you back off the adjustment too much, and pull the valve out of full pressure, you take the usual risk...not enough pressure=burned clutches.

 

[Cranky]

When you crack open the throttle, does the kickdown linkage move too? If not, it's not right....

 

[AR67GTX]

When you crack open the throttle, does the kickdown linkage move too? If not, it's not right....

Yes - the transmission linkage spring pulls the upper transmission rod forward against the carb throttle arm pin so any movement of the throttle moves the upper transmission rod rearward. This is not a close up but I think you can see the set up. Can't swear all the pieces are correct length for a 67 (and the carb is obviously not) but it's set up like the 67 shop manual.



Went for my test drive and couldn't really tell it drove any differently. Still shifts to 2nd and 3rd quickly at a partial throttle take off. Still has kickdown OK when throttle is close to floored. Shifts are firm. Didn't try a full banzai run due to all the holiday traffic.

 

[AR67GTX]

Here are better photos - first with everything hooked up.



This one I disconnected the transmission linkage return spring so you can see how much free play it has before it meets any resistance at the transmission throttle valve.

 

[furyus]

I know from working with my Dart, there's supposed to be some play before you feel tension on the transmission lever. You can also adjust the KD by opening the carb all the way, and make sure the trans lever is almost all the way back. I fine tune it from there. If that doesn't work, it could be the levers are incorrect. My issues turned out to be the trans lever was the right length, but the locating flat was clocked differently from the lever that worked. Also, I had a 4 speed AVS carb, and i think the carb lever was different from the automatic AVS carb linkage.

 

[AR67GTX]

I think my Edelbrock carb could be a little of the problem. If you look closely in the two above pictures you will see a coupler on the rod and that's because if I were to straighten it out, it would still be about a quarter inch short of being able to install it with the rear of the slot up against the carb throttle pin. The older photo in post #14 doesn't have it but I couldn't get the back of the slot up to the pin and I had kickdown issues (as in sometimes it wouldn't). It's been awhile so I don't remember all the details at the time. I probably need a correct carb but unfortunately not a lot of correct 750 AFBs or AVSs lying around for the asking.

 

[miller]

The upper rod - I adjusted with the throttle held wide open and the transmission lever pushed all the way to the rear - with 1/4 inch additional slot clearance to avoid bottoming the transmission valve.

I happen to have a copy of the 67 manual...and, just read through the adjustment. Here's what I read, and got from it. (I'm not trying to give you a hard time! Just trying to make things clear...okay?)

The 1/4" clearance your mentioning is NOT for the kick-down linkage. It's for the throttle cable itself, at the hold down.

For the slotted kick-down adjustment, it says at WOT, and the kick-down linkage pushed all the way to the rear...the rear end of the slot should fit over the carb throttle arm pin...with no resistance.
In other words, with a slight amount of clearance, between pin and rear of slot.
And, once hooked up (without spring) should move full swing, with no binding.

Gonna leave it at that.

 

[Cranky]

What are the shift points with normal driving?

 

[oldbee]

Ar67 sounds like you got it. Cranky mine at "very normal" driving is in 3rd by 15mph.Stock trans, no "kits" or anything.