727 shift strategy help

[///Matt]

I’ve got a 727 behind a 440, both out of some 1977 donor vehicle that I cannot identify. The trans has been “customized” with a special-order converter and some kind of shift kit, but I can’t tell you what, because the PO couldn’t tell me.

What I CAN tell you is that it shifts 1st-2nd gear wayyyy too early (like 2500 rpm, even with WOT), then stays in 2nd for a long time, up to around 4500-5000 even with gente throttle.

What would you look into first? Accumulator springs? Just throw a new “known” valvebody and springs in there? Maybe kickdown tension/ratio is wrong? (It was a 318/904 car at birth)

Halp.

 

[451Mopar]

I'd start with going through the valve body and making it was assembled correctly.
While it is out, air pressure check the clutches and servos.

I was working on a 727 a few years ago, that someone put a shift kit in. It had both the original separator plate and the one from the shift kit installed.

 

[///Matt]

I'd start with going through the valve body and making it was assembled correctly.
While it is out, air pressure check the clutches and servos.

I was working on a 727 a few years ago, that someone put a shift kit in. It had both the original separator plate and the one from the shift kit installed.

Bet that shifted real well!

 

[R/T Boy 67]

First thing I would do is make sure kickdown linkage is operating as it shoud be.

 

[///Matt]

First thing I would do is make sure kickdown linkage is operating as it shoud be.

Is there a spot where I can find a spec to check a swing measurement or something? As its a transplant, I’m not totally sure that the gas pedal get WOT, or that the kickdown linkage makes it to kickdown. How far does the kickdown lever on the trans have to swing to make it go?

 

[miller]

Hey, ///Matt, in a nutshell, where the kickdown rod(s) hook up, both ends, you want the same travel distance to match. That's both at the trans lever, and where it hooks to the carb linkage.
Setting it, at WOT, the trans lever almost full, with a little clearance so it doesn't bottom out.

 

[///Matt]

Hey, ///Matt, in a nutshell, where the kickdown rod(s) hook up, both ends, you want the same travel distance to match. That's both at the trans lever, and where it hooks to the carb linkage.
Setting it, at WOT, the trans lever almost full, with a little clearance so it doesn't bottom out.

Turns out my lokar cable bracket decides to move itself from time to time, throwing the throttle cable and kickdown cable both out of whack.... made some changes, we’ll see it it’s a different animal now!

 

[khryslerkid]

I was adjusting mine last week. It doesn't take much. Mine is just a rod that goes from the carb to the trans leaver, no bell crank. Lengthening it makes the shifts later, shorting it makes the shifts sooner. I was changing it about 1/8" at a time. A 1/4" will make a big difference.

Your FMS will show you just how to do it if you have a bell crank. There's a procedure for them.

 

[MrJLR]

Always better to shift later than sooner


Jeff

 

[khryslerkid]

Always better to shift later than sooner


Jeff

My '62 was shifting too soon. I couldn't even feel the one two and third happened at 20 mph. I checked the FSM and they show a chart, one mph reference at idle and another for wide open throttle? So I just lengthened the rod 1/4". Well that made a difference, 2nd was a little hard at 25 mph and 3rd didn't happen until 40 mph. So I shortened it 1/8" and that was better but It still had a hard one/two. Shortened it 1/16" and now it's perfect. Surprising how sensitive it is.

 

[MrJLR]

My '62 was shifting too soon. I couldn't even feel the one two and third happened at 20 mph. I checked the FSM and they show a chart, one mph reference at idle and another for wide open throttle? So I just lengthened the rod 1/4". Well that made a difference, 2nd was a little hard at 25 mph and 3rd didn't happen until 40 mph. So I shortened it 1/8" and that was better but It still had a hard one/two. Shortened it 1/16" and now it's perfect. Surprising how sensitive it is.

90% of the shifting problem threads are because of the throttle pressure ( kick down ) adjustment.

Jeff

 

[///Matt]

Hey, ///Matt, in a nutshell, where the kickdown rod(s) hook up, both ends, you want the same travel distance to match. That's both at the trans lever, and where it hooks to the carb linkage.
Setting it, at WOT, the trans lever almost full, with a little clearance so it doesn't bottom out.

Hey Miller... with the “so it doesn’t bottom out” part: is there any reason for that other than the posibility of preventing full-throttle?

Like: if it bottoms out, but I still get WOT, am i hurting anything?

My lokar cables are trimmed a bit short, and I cannot slack the kickdown cable anymore... it bottoms out the kickdown lever on the trans during WOT... but I also reach full-on WOT at the carb, so am I ok?

 

[khryslerkid]

Hey Miller... with the “so it doesn’t bottom out” part: is there any reason for that other than the posibility of preventing full-throttle?

Like: if it bottoms out, but I still get WOT, am i hurting anything?

My lokar cables are trimmed a bit short, and I cannot slack the kickdown cable anymore... it bottoms out the kickdown lever on the trans during WOT... but I also reach full-on WOT at the carb, so am I ok?

You should be ok. The real test is when you drive it, where it shifts. The more pressure that is on the kickdown the longer it takes to shift between gears. If there is too much time between shifts, shorten the lenth only about a 1/8" at a time. It doesnt take much.

 

[miller]

Hey Miller... with the “so it doesn’t bottom out” part

Simply so none of the linkage gets into a bind. With a cable, probably okay. The lever on the trans is spring loaded, for return, and the first half of movement doesn't do anything. That's why you want 'almost' full travel...then, final adjusting to get the shift points where you want them. That full travel point, is fairly sensitive, only takes small adjustments, for the shift points.

 

[///Matt]

Thanks guys

 

[sputnik 440]

I have the identical problem manual shift kit and all. I worked with a mechanic and he replaced the governor because it wouldn't down shift until the car was totally stopped. He replaced the entire valve body with "stock" parts. He made a new bracket to the way the kickdown cable connected to the FAST efi (same adjustment as for carb). So, with all that, and many attempts to adjust the kickdown, the Duster (383) now shifts good at 1-2 (2500-3000 rpms) and rather smooth. The problem is the 2 -3 (46 mph and about 4500 rpms) and a hard shift. It will shift sooner if you let off the throttle slightly before you get to 45. When you do that you really get a hard shift. WOT I can live with behavior, shifting is smoother and at acceptable shift point in 1-2 and 2-3. Passing gear is also acceptable.
The main problem is the 2-3 shift at normal acceleration and when I get off the throttle while in 2nd. I am running a 391 rear end and have right around 420 hp. Any advise? I am going to take it back to mechanic and would like to tell him what to try. He doesn't think the adjustment on the kickdown is a problem. He has spent much time on adjusting it, ever so slightly, to give the best performance. Thanks.

 

[MrJLR]

I have the identical problem manual shift kit and all. I worked with a mechanic and he replaced the governor because it wouldn't down shift until the car was totally stopped. He replaced the entire valve body with "stock" parts. He made a new bracket to the way the kickdown cable connected to the FAST efi (same adjustment as for carb). So, with all that, and many attempts to adjust the kickdown, the Duster (383) now shifts good at 1-2 (2500-3000 rpms) and rather smooth. The problem is the 2 -3 (46 mph and about 4500 rpms) and a hard shift. It will shift sooner if you let off the throttle slightly before you get to 45. When you do that you really get a hard shift. WOT I can live with behavior, shifting is smoother and at acceptable shift point in 1-2 and 2-3. Passing gear is also acceptable.
The main problem is the 2-3 shift at normal acceleration and when I get off the throttle while in 2nd. I am running a 391 rear end and have right around 420 hp. Any advise? I am going to take it back to mechanic and would like to tell him what to try. He doesn't think the adjustment on the kickdown is a problem. He has spent much time on adjusting it, ever so slightly, to give the best performance. Thanks.

I still stand by my statement from earlier....
It's "almost" always in the throttle pressure (kick-down linkage) adjustment.
Although I can't speak for his valve body work.....

Jeff

 

[sputnik 440]

Jeff, I hear you and all the others loud and clear and totally concur, however, I watched the guy make finite adjustments, only to move away from the shift points and hardness of shifts. I will have him go through it one more time. Can you think of anything else? How about the weight of the governor? Does that effect the shift points or smoothness of shift? He mentioned it might be in the 2nd gear spring. Could that be? I do not know what he is referring to. I need to find the time to read the 727 Torque flight book.

 

[MrJLR]

Jeff, I hear you and all the others loud and clear and totally concur, however, I watched the guy make finite adjustments, only to move away from the shift points and hardness of shifts. I will have him go through it one more time. Can you think of anything else? How about the weight of the governor? Does that effect the shift points or smoothness of shift? He mentioned it might be in the 2nd gear spring. Could that be? I do not know what he is referring to. I need to find the time to read the 727 Torque flight book.

I hear ya....
The governor absolutely effects shift points.....the shift firmness if in the valve body.
They sell different governors specifically to change shift points.
When I rebuilt my 727 my governor was very sticky...I went to great lengths to clean it so everything moved freely.
Once the transmission was back in the car, it took a LOT of adjusting of the throttle pressure linkage (a lot!) to get it just right...seemed like I chased it forever....!

Jeff