Shifting - What am I missing.

[Pawned]

I have a 71 duster with a newly rebuilt 318 and original 3 speed automatic xmission and rear end.

The car was shifting into 3rd at 41 mph. I do not have a tach on it to tell you rpms. After the engine was rebuilt it started shifting into 3 in the mid to high 20 mphs. All seemed normal and right with the world.
It is less than 100 miles later and the transmission has gone back to shifting into 3rd at appx 45mph and automatically down shifts to 2nd at 37 mph.

I think the xmission and rear end are original to the car.
Is this a vacuum problem (something simple) or the xmission needs work.

The last couple days I have been troubleshooting why the backup lights did not work. I figured it is a problem in the transmission or the neutral switch. The switch in new, So I hard wired a switch on the dashboard that I can manually turn on the backup lights. Is it possible that the wiring I did caused the problem?
It would only take a few minutes to change the wiring back to what it was.


Inquiring mind wants to know

 

[oldkimmer]

.......................Check to see if the spring on the kd linkage came off and is allowing the linkage to be on too much, u can check a factory service manual to see the correct adjustment and proper procedure to adjust it..........ur wiring job did not cause this.......kim.........

 

[godfatherofchry]

you need to look up the thread with the factory training film on mopar trans and if you Wight to the end of the film there is a lot of other ones too its very educational........Artie

not that we don't like telling you that explains it with pictures.......

 

[Pawned]

you need to look up the thread with the factory training film on mopar trans and if you Wight to the end of the film there is a lot of other ones too its very educational........Artie

not that we don't like telling you that explains it with pictures.......

.......................Check to see if the spring on the kd linkage came off and is allowing the linkage to be on too much, u can check a factory service manual to see the correct adjustment and proper procedure to adjust it..........ur wiring job did not cause this.......kim.........

First- thank you for taking the time and effort to help me.

Please forgive my lack of knowledge in the matter, What and/or where is the kd linkage. I did a search for "kd" in the 70 service manual and came up zip.

There are tons of videos or the FACTORY TRAINING FILM ON MOPAR TRANSMISSION, which one are you referring to?

 

[TrailBeast]

The KD linkage is attached to the throttle linkage at the carb, and runs down the back of the engine to a lever on the drivers side of the trans.
It is the rod with the long slide area built into it.
At idle, that rod should be all the way forward (towards the radiator) and at full throttle it should be as far back as it can go.
It should have a return spring on it to make it return forward like this picture.
At idle, it should look just like this picture.
I suspect you will find that yours is half way back or more at idle.

 

[Pawned]

Thank you, thank you, thanx. now all I have to do is have it not jump to fast idle. But I am still working on that.
Becoming a Gold member here, was the best purchase I made with regards to the car.

 

[Pawned]

Now my shifting problems are reversed. I followed TrailBeast's advice and it stopped the car shifting into 3 at 41mph.
Now it is going into 2 at 5mph and 3 at about 7to 8 mph. I have been playing around with the KD linkage but getting nowhere.
Help, please

 

[440Ken]

The linkage that goes to the transmission needs to be shortened. The slotted rod needs to be screwed clockwise two or three turns. That will decrease the throttle pressure and make it shift sooner.

 

[fishy68]

Now my shifting problems are reversed. I followed TrailBeast's advice and it stopped the car shifting into 3 at 41mph.
Now it is going into 2 at 5mph and 3 at about 7to 8 mph. I have been playing around with the KD linkage but getting nowhere.
Help, please

What did you do to it?

The way the kickdown linkage (it's actually called throttle pressure linkage) works is the longer you adjust the rod by the carb the faster you will have to go before it shifts into the next gear. My starting procedure for adjusting it is to adjust the rod by the carb so that it's pushing the linkage all the way back as far as it'll go without binding when the carburetor is held wide open. Most of the time that works no problem but sometimes you run into one that'll hang in gear too long and you need to shorten the rod. Some are very touchy so as little as a 1/2-1 turn on the rod makes quite a difference. Others are not so touchy and take 2-3 turns to make a difference.

BTW: yours does look like the setup in the picture Trailbeast posted, correct? Some time in the early 70's they changed the linkage style. If yours doesn't look like the one in the pic they work the same but the adjustment procedure is different due to the change

 

[TrailBeast]

Now my shifting problems are reversed. I followed TrailBeast's advice and it stopped the car shifting into 3 at 41mph.
Now it is going into 2 at 5mph and 3 at about 7to 8 mph. I have been playing around with the KD linkage but getting nowhere.
Help, please

Try small adjustments at a time (1-2 turns on the adjuster) and test drive it.

 

[Pawned]

Try small adjustments at a time (1-2 turns on the adjuster) and test drive it.

I have been trying that, should I make the rod shorter, which will put bring the carb closer to the right side of the rod. Or should I make it longer which will bring the carb lever closer to the left side of the rod?
There currently is about 3/4" gap on the left side

Thanks

 

[Bad Sport]

I have been trying that, should I make the rod shorter, which will put bring the carb closer to the right side of the rod. Or should I make it longer which will bring the carb lever closer to the left side of the rod?
There currently is about 3/4" gap on the left side

Thanks

Can you post a pic of what's going on at the carb?

 

[grumpuscreature]

Try what fishy68 suggested. Throttle held wide open and adjust linkage until kickdown lever on the trans is as far rearward as it will go. If adjusted properly the carb stud will just be kissing the front of the slot in the linkage at idle with the spring disconnected.

 

[Pawned]

Can you post a pic of what's going on at the carb?

This is the setup now. I could swear when I last left it the rod and springs were setting on the workbench. CRS disease

 

[Pawned]

The linkage that goes to the transmission needs to be shortened. The slotted rod needs to be screwed clockwise two or three turns. That will decrease the throttle pressure and make it shift sooner.

That is just the opposite of my problem

 

[toolmanmike]

Shouldn't the gap between the post and the end of the slot be closer for proper adjustment? The tighter the gap the higher the shift points I always thought. Correct me if I'm wrong. It has been years since I messed with one of these. tmm

 

[Bad Sport]

Is that a bolt or something in the rear of that slot? And why is it there? The slotted piece will adjust out to the pin on the carb won't it?

At WOT where is the arm on the trans, all the way back?

That return spring concerns me as well, it looks like it's maxed out. I would seriously consider redoing that, and adding a dual spring set up. If that spring breaks when you're mashing on it, that could be a problem. It isn't related to your shifting issue though.


Edit: Is the small spring on the throttle pressure rod slack, or am I imagining things. If it is, then you might replace that as well, so it keeps the rod forward where it should be.

It looks like a simple adjustment might cure your problem.

 

[Bad Sport]

Shouldn't the gap between the post and the end of the slot be closer for proper adjustment? The tighter the gap the higher the shift points I always thought. Correct me if I'm wrong. It has been years since I messed with one of these. tmm

At rest there should be about 1/16th of an inch, maybe a tad more from the rear edge of that slot and the pin. It looks like there is a bolt or something there.

 

[toolmanmike]

Is that a bolt or something in the rear of that slot? And why is it there? The slotted piece will adjust out to the pin on the carb won't it?

At WOT where is the arm on the trans, all the way back?

That return spring concerns me as well, it looks like it's maxed out. I would seriously consider redoing that, and adding a dual spring set up. If that spring breaks when you're mashing on it, that could be a problem. It isn't related to your shifting issue though.

I enlarged the photo and it doesn't look like a bolt in there, just what you can see of the carb through the slot. That's an old trick when you change carbs and run out of thread on the rod.

 

[Bad Sport]

I enlarged the photo and it doesn't look like a bolt in there, just what you can see of the carb through the slot. That's an old trick when you change carbs and run out of thread on the rod.

That's why I was asking. I did too, but can't really tell. If there is that big of a gap there, then that's the issue.

 

[6pk2goDemon]

Pawned, If you can't get it figured out with the guys help here, we can come help you tomorrow or ??

You have my #

 

[Pawned]

This is the setup now. I could swear when I last left it the rod and springs were setting on the workbench. CRS disease

I experimented, I kept turning the rod clockwise to keep the throttle rod opening away from the throddle linkage.

I printed out some pages from the service manual, I am going to try that again. It makes more sense than it did yesterday. guess I needed fresh eyes

 

[Pawned]

Pawned, If you can't get it figured out with the guys help here, we can come help you tomorrow or ??

You have my #

you don't have to drive all this way out here. I can come to you. You still have my phone number???

 

[6pk2goDemon]

PM it to me again please....

 

[TrailBeast]

Get some tension on that throttle pressure rod spring, as it looks too loose to do any good.
The spring should always return the rod to the full forward position.
I think your adjustments may stabilize if you tension up on that spring.