A904 Hard 1-2 Shift and Reverse

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I would recommend before you start shotgunning the issue be sure you have an issue.

IMHO go back and adjust the kick down PER THE FACTORY SHOP MANUAL.

THEN run through the diagnostics as outlined in the FSM for shift points and feel

For all you know a previous owner installed a shift kit.

Also what are you comparing to, to determine your shift is too firm.
 
It's not the kickdown; kd affects both shifts. It's probably not the front band either, but adjusting it is simple maintenance. A shift kit isn't going to cause a late hard 1-2 shift and leave the 2-3 shift acceptable; unless it was installed wrong. If the front band is super loose; causing the late hard 1-2, then there should be spinup between 2-3.
 
Dana67Dart said:
I would recommend before you start shotgunning the issue be sure you have an issue.

IMHO go back and adjust the kick down PER THE FACTORY SHOP MANUAL.

THEN run through the diagnostics as outlined in the FSM for shift points and feel

For all you know a previous owner installed a shift kit.

Also what are you comparing to, to determine your shift is too firm.
Click to expand...
I've got some reading to do! You are right about the history of the car, you just don't know what has been done to it. But as I stated at the beginning, this car is original, all the mechanicals need refurbishing. Well, I am comparing it to 2nd to 3rd is like butter and don't even realize I am in 3rd gear it is so smooth. 1st-2nd the car shakes, its abrupt and hard. Thank you for pointing me in the right direction all of Y'all.
 
Dana67Dart said:
I would recommend before you start shotgunning the issue be sure you have an issue.

IMHO go back and adjust the kick down PER THE FACTORY SHOP MANUAL.

THEN run through the diagnostics as outlined in the FSM for shift points and feel

For all you know a previous owner installed a shift kit.

Also what are you comparing to, to determine your shift is too firm.
Click to expand...
By kickdown do you mean adjust the bands like this?
upload_2021-1-30_23-43-22.png

upload_2021-1-30_23-44-13.png

upload_2021-1-30_23-46-4.png
 
The hard shift is more than likely that the shuttle valve is stuck in its bore. U have to remove the valve body to check it. May also have a blocker rod under the accumulator. Kim
 
He's talking about adjusting the kd lever, not the kd band. To adjust the kd band, just loosen the locknut like half a turn, then hold it from turning, and turn the stud clockwise until it stops. Back it out about two turns. Hold the stud from turning and tighten down the locknut. Test drive. But oldkimmer is probably right; just a lot more involved with fixing. The kd lever in the pic is calling it the throttle lever. That throtle/kd lever should be all the way back when the carb is all the way open.
 
CudaFactHackJob said:
Maybe your front band is too loose.
Click to expand...

I'm no expert for sure, but it seems to me like if the band was too loose it would cause a slow, smooth, almost slipping engagement. And if it was too tight, it would hit hard. Maybe I'm thinking about it backwards? Help me learn!
 
Is the engine taking a lot of throttle to take off with?

What everyone calls the KD mechanism, is actually a throttle-pressure adjuster, with the KD being a function of that. But think of that mechanism as firstly being the throttle pressure adjuster.
So as the throttle is opened, it pushes the slotted member rearwards increasing the throttle pressure at the trans. This does two things, it fights the governor as to when the shift will occur, delaying the roadspeed at which the trans will shift. And since the pressure is higher, the shift will be harsher.
Ok, so if the engine is down on power, you will naturally drive deeper into the carb, using more than normal throttle. and so I repeat; Is the engine taking a lot of throttle to take off with?
The why of the engine being down on power is another matter, from as simple as needing a tune-up, to a frozen stator in the convertor, to not running on all cylinders.

In reverse, all pressure regulation is bypassed, and the L/R servo gets whatever the pump can put out which can max out ~275 psi.
If the throttle pressure valve is being adjusted by the KD mechanism, the pressure will be higher than normal, which being maybe 90psi. By lengthening the KD rod, you increase the Part Throttle pressure. Bad idea. Especially if that now limits your throttle opening. And this is what @CudaFactHackJob is trying to get you to understand.

Now, you keep thinking the car is all original, but if the rear end has been swapped to one with a higher Torque Multiplication, then it will spin the driveshaft up faster, commanding an earlier shift. This calls for a reduction in throttle pressure to prevent delayed harsh upshifts. Or a reduction in governor pressure to get back on track.

So you could have multiple issues.
I recommend a compression test, and to at least set the timing after proving the balancer mark; to see if you even have an engine. And then a stall test.
And finally, figure out your rear gear ratio, and compare it to what it came from the factory with, if you can. Alternatively, figure out if the trans in there is what it left the factory with, if you can.
But I repeat; Is the engine taking a lot of throttle to take off with? This could be a sign of a bad TC.
 
69 Barracuda vert said:
Yes it is on curb idle now. Where should the slotted rod be located when at curb idle?
Click to expand...
This is of little consequence.
What matters is that the WOT setting on the carb is synchronized to the all-the-way-back setting of the KD mechanism .... AT THE TRANS.
So then, with the engine OFF, you push the KD all the way back until it stops hard, and hold it there. Then open the throttle as far as it will go... until the pin hits the back of the slot. Now, if the throttle is not yet fully open, then move the slot by screwing it further onto the shaft back and repeat ... as often as necessary until you find synchronicity.
But if with the KD ALL the way back, and the carb at WOT, if you still have room between the pin and the back of the slot, this is not necessarily a bad thing., if the trans is already hard shifting. If you think you need to, you can increase that gap.
But in so doing, you are reducing the throttle pressure, and if it gets to be too low, you risk slipping the clutches and bands and ultimately, a trans failure. So when operating in this mode, you have to be sensitive to the symptoms of slipping clutches and bands.
If you get into this kind of situation, you need to look at the rest of the combo. Such as low engine power, wrong governor weights, or bad TC.
Ok, that's all I got.
 
AJ/FormS said:
Is the engine taking a lot of throttle to take off with?

What everyone calls the KD mechanism, is actually a throttle-pressure adjuster, with the KD being a function of that. But think of that mechanism as firstly being the throttle pressure adjuster.
So as the throttle is opened, it pushes the slotted member rearwards increasing the throttle pressure at the trans. This does two things, it fights the governor as to when the shift will occur, delaying the roadspeed at which the trans will shift. And since the pressure is higher, the shift will be harsher.
Ok, so if the engine is down on power, you will naturally drive deeper into the carb, using more than normal throttle. and so I repeat; Is the engine taking a lot of throttle to take off with?
The why of the engine being down on power is another matter, from as simple as needing a tune-up, to a frozen stator in the convertor, to not running on all cylinders.

In reverse, all pressure regulation is bypassed, and the L/R servo gets whatever the pump can put out which can max out ~275 psi.
If the throttle pressure valve is being adjusted by the KD mechanism, the pressure will be higher than normal, which being maybe 90psi. By lengthening the KD rod, you increase the Part Throttle pressure. Bad idea. Especially if that now limits your throttle opening. And this is what @CudaFactHackJob is trying to get you to understand.

Now, you keep thinking the car is all original, but if the rear end has been swapped to one with a higher Torque Multiplication, then it will spin the driveshaft up faster, commanding an earlier shift. This calls for a reduction in throttle pressure to prevent delayed harsh upshifts. Or a reduction in governor pressure to get back on track.

So you could have multiple issues.
I recommend a compression test, and to at least set the timing after proving the balancer mark; to see if you even have an engine. And then a stall test.
And finally, figure out your rear gear ratio, and compare it to what it came from the factory with, if you can. Alternatively, figure out if the trans in there is what it left the factory with, if you can.
But I repeat; Is the engine taking a lot of throttle to take off with? This could be a sign of a bad TC.
Click to expand...
Yes AJ, it feels very rough taking off and more pedal than should be.
 
69 Barracuda vert said:
Yes AJ, it feels very rough taking off and more pedal than should be.
Click to expand...
well there you have it; mystery solved.
Fix that and your trans issues should simultaneously disappear.
I would start by making sure that the plug wires to numbers 5 and 7 are not crossed in the cap, and well separated from cap to plugs, and if good, then isolating the cylinders one by one to see if all cylinders are working. You should see a similar rpm drop on every cylinder. After that, a compression test is next. And when you do that, it is best to have all plugs out and the carb blocked WOT. Then crank each cylinder until you get two consecutive same or near same readings. I like to record the number of pumping cycles it took to reach the maximum, cuz if one takes twice as many as the others, you know something is up. Also at this time, you can study the plugs to see if it's worth putting them back in. Sometimes a cracked insulator is very difficult to see, yet the coil will instantly not fire it. Sometimes the engine will idle on it, but will refuse to respond properly as you roll in the throttle. I have never had a new plug do that, but other mechanics say they have seen it.

BTW numbers 5 and 7 wires must NOT be strung together with zipties. This encourages induction firing between them , causing the #7 to fire on the intake stroke, which is bad. Those two wires should never run side by side, for any length, and always be separated by a minimum 1 inch. The cheaper the wire, the more important this is. You can cross one wire over the other at less than 1 inch, but the crossing should be as close to 90* as you can make it, and not touching.

May all your luck be Good luck.
 
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AJ/FormS said:
By lengthening the KD rod, you increase the Part Throttle pressure. Bad idea. Especially if that now limits your throttle opening. And this is what @CudaFactHackJob is trying to get you to understand.
Click to expand...
Thank AJ for your help.
With the car warmed up and the carb on curb idle, I removed the spring and the KD rod was too long and 1/2" from the pin
AJ/FormS said:
Is the engine taking a lot of throttle to take off with?

What everyone calls the KD mechanism, is actually a throttle-pressure adjuster, with the KD being a function of that. But think of that mechanism as firstly being the throttle pressure adjuster.
So as the throttle is opened, it pushes the slotted member rearwards increasing the throttle pressure at the trans. This does two things, it fights the governor as to when the shift will occur, delaying the roadspeed at which the trans will shift. And since the pressure is higher, the shift will be harsher.
Ok, so if the engine is down on power, you will naturally drive deeper into the carb, using more than normal throttle. and so I repeat; Is the engine taking a lot of throttle to take off with?
The why of the engine being down on power is another matter, from as simple as needing a tune-up, to a frozen stator in the convertor, to not running on all cylinders.

In reverse, all pressure regulation is bypassed, and the L/R servo gets whatever the pump can put out which can max out ~275 psi.
If the throttle pressure valve is being adjusted by the KD mechanism, the pressure will be higher than normal, which being maybe 90psi. By lengthening the KD rod, you increase the Part Throttle pressure. Bad idea. Especially if that now limits your throttle opening. And this is what @CudaFactHackJob is trying to get you to understand.

Now, you keep thinking the car is all original, but if the rear end has been swapped to one with a higher Torque Multiplication, then it will spin the driveshaft up faster, commanding an earlier shift. This calls for a reduction in throttle pressure to prevent delayed harsh upshifts. Or a reduction in governor pressure to get back on track.

So you could have multiple issues.
I recommend a compression test, and to at least set the timing after proving the balancer mark; to see if you even have an engine. And then a stall test.
And finally, figure out your rear gear ratio, and compare it to what it came from the factory with, if you can. Alternatively, figure out if the trans in there is what it left the factory with, if you can.
But I repeat; Is the engine taking a lot of throttle to take off with? This could be a sign of a bad TC.
Click to expand...
Yes AJ, I have to figure out what I have in the drive train. The engine runs smooth, no misses or valve noise with original wires, plugs have been replaced recently and I just re-gap them. All the plugs looked great without carbon so that should tell me all cylinders are firing. I will do a leak down test at each cylinder to find compression. Points need to be changed, good rotor and cap. I will check timing today. The carb is the BBD 2bbl and has remanufacture sticker on it from Holly. It is leaking and the car shut off at a stop light from a stuck float so, I am going to re-build the carb soon. But, with the engine running smooth, seems strong, once I get the linkage and trans sorted it should run a lot stronger from a stop, it just seems rough. Engine has never been out of the car per seller (2nd owner had it for 5 years). I will also do what you said with the KD and carb adjustments.
 
AJ/FormS said:
well there you have it; mystery solved.
Fix that and your trans issues should simultaneously disappear.
I would start by making sure that the plug wires to numbers 5 and 7 are not crossed and well separated, and if good, then isolating the cylinders one by one to see if all cylinders are working. You should see a similar rpm drop on every cylinder. After that, a compression test is next. And when you do that, it is best to have all plugs out and the carb blocked WOT. Then crank each cylinder until you get two consecutive same or near same readings. I like to record the number of pumping cycles it took to reach the maximum, cuz if one takes twice as many as the others, you know something is up. Also at this time, you can study the plugs to see if it's worth putting them back in. Sometimes a cracked insulator is very difficult to see, yet the coil will instantly not fire it. Sometimes the engine will idle on it, but will refuse to respond properly as you roll in the throttle. I have never had a new plug do that, but other mechanics say they have seen it.

BTW numbers 5 and 7 wires must NOT be strung together with zipties. This encourages induction firing between them , causing the #7 to fire on the intake stroke, which is bad. Those two wires should never run side by side, and always be separated by a minimum 1 inch. The cheaper the wire, the more important this is. You can cross one wire over the other at less than 1 inch, but the crossing should be as close to 90* as you can make it, and not touching.

May all your luck be Good luck.
Click to expand...
All good...5 & 7 are not getting near each other.
barracuda 001.jpg
barracuda 002.jpg
 
What do you mean, "Points need to be changed"?? Don't mess around with used points. Points are the first thing to check in an old motor. New points are the first thing to install if there's any type of problem in an old motor. Better yet, pick up an HEI distributor off ebay for $50.99 free shipping and solve all your ignition problems. 90% of carburetor problems are the points...But I bet that won't solve your harsh 1-2..
 
Also check the vacuum advance diaphragm. At Part throttle, light throttle, it should start advancing at about 1500 to 1700 rpm, or at least before stall speed. If it does not, and your idle timing is still at 5*BTDC, the power will suck.
The V-can adds it's timing to the base timing. IDK what your V-can is tuned for but 13/14 is typical. By the time you hit stall rpm, the mechanical might be up to 10* .. So adding those up at light to medium throttle, it might total 28 to 30 degrees, making for a smooth and relatively powerful take off. Without the Vcan, all you get is the 5*+10=15. and if the mechanical is frozen, then just 5* will be super lazy. I don't think the engine would be shaky or rough tho just from lack of timing.
However, if the mechanical advance mechanism is frozen at full advance, and this occurred after the base-timing was set, that engine will for sure shake with the application of throttle. because now it is getting perhaps 35* at idle, plus the Vcan, as you roll in the throttle, maybe 50*. No 318 I know of will like that. and shaking is it's way of complaining about it. It will idle just fine on 25*, your only clues are a high idle; and a stumble on throttle tip-in, if you slow the idle down. It might even like more than 25* at idle; it just won't complain about it until it is required to pull.
 
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69 Barracuda vert said:
Thank AJ for your help.
With the car warmed up and the carb on curb idle, I removed the spring and the KD rod was too long and 1/2" from the pi
Click to expand...
this is wrong and meaningless.
The KD sync has to be done at WOT at the carb, and the linkage rammed as far back as it goes. Where it ends up at idle is of no consequence. Nothing inside the trans is affected until you feel resistance to the rearward travel of the linkage. And max throttle pressure does not occur until the linkage is in the full rearward position, jammed internally to full stop.
Where it ends up at idle, after the syncing, is of no consequence and all that return spring does is keep it from flopping around and rattling. EDIT: see post 47
However, if your VB has a PT KD add-on, then you can use some slack to tune that device. But the PT KD did not come on V8s until 1971.
 
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PT=part throttle..he's confuzzled enough ..But ya know what; I left the spring off before and my kd would stick back a bit and cause late shifts.
 
CudaFactHackJob said:
What do you mean, "Points need to be changed"?? Don't mess around with used points. Points are the first thing to check in an old motor. New points are the first thing to install if there's any type of problem in an old motor. Better yet, pick up an HEI distributor off ebay for $50.99 free shipping and solve all your ignition problems. 90% of carburetor problems are the points...But I bet that won't solve your harsh 1-2..
Click to expand...
Ive only had the car for 10 days Cuda! The car is 51 years old and nothing ever changed (that I can tell) so, I decided to start with safety issues 1st, steering (total rebuild entire front suspension) with a disc brake conversion, new stainless brake and fuel lines and a fuel tank. The trans was an "I'll get to it" thought. However, while I am waiting on all the parts to arrive I would pose a question about the trans to the experts of Mopars. And, the 1st thing I checked was the points, cap and rotor and yes they have gone on a long list. For you Cuda I will put them in today. Thanks for your help.
 
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