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Can I fix the delayed 1-2 manual shift on my 727?

Posted By: DaveRS23

Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 03:55 PM

727 with Trans-Go shift kit, 5,800 A&A gov, and 4,000 PTC converter. 3.91 rear gears in a street/strip car. I have been running this tranny for a while and it works real well. Good automatic shifts and right on 5,800. But if I jump on it with the selector in 1 and manually shift to 2, the delay for it to shift to 2nd is enormous, often hitting the rev limiter.

No matter how early I slip the shifter to 2, the actual shift is way late. The 2-3 shift is right after the shifter is moved, so the delayed manual 1-2 shift is the only issue I have with this tranny.

This is not the first tranny I have had that has a delayed manual 1-2 shift, but this one seems to be a bit more exaggerated than others.

Any way to get the tranny to go into 2nd when I move the shifter? And no, I don't want to put a manual valve body in.

Thanks!
Posted By: Challenger 1

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 04:37 PM

Quote:

727 with Trans-Go shift kit, 5,800 A&A gov, and 4,000 PTC converter. 3.91 rear gears in a street/strip car. I have been running this tranny for a while and it works real well. Good automatic shifts and right on 5,800. But if I jump on it with the selector in 1 and manually shift to 2, the delay for it to shift to 2nd is enormous, often hitting the rev limiter.

No matter how early I slip the shifter to 2, the actual shift is way late. The 2-3 shift is right after the shifter is moved, so the delayed manual 1-2 shift is the only issue I have with this tranny.

This is not the first tranny I have had that has a delayed manual 1-2 shift, but this one seems to be a bit more exaggerated than others.

Any way to get the tranny to go into 2nd when I move the shifter? And no, I don't want to put a manual valve body in.

Thanks!



I don't know anything about them. I know I have 2 727s from Coan Trans in Kokomo Ind that absolutely destroy the tires on the 1-2 shift whenever I shift it manually or in full auto and they do not have manual valve body's in them. Very firm shifts for both shifts and have lasted a long time now, could not be happier with both trans.
Posted By: Paul_Fancsali

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 05:09 PM

My 727 has a Darrell Young shift kit in it from trans shop The car shifts great compared to the last one with man valve body. Never go back. This trans was built in 1990 and still acts like new 30K + later

By the way your car will be faster if you leave it shift in drive all you are doing now is slowing down your car by man shifting
Posted By: lewtot184

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 05:19 PM

back off the throttle pressure on the kick down rod.
Posted By: Silver70

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 05:44 PM

You can remove the accumulator spring.
Posted By: JohnRR

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 06:01 PM

What kind of front band , what lever ratio, what is your rev limiter set at ?

The 1-2 shift is nothing more than the front band stopping the front drum from spinning, you are adding in the rear servo releasing the rear drum though?
Posted By: GTX MATT

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 06:09 PM

What RPM are you manually shifting at?
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 07:29 PM

The tranny has the rigid (not flex) band, and the rev limiter is set at 6,500. I believe the lever is a 4.2. I don't remember if the accumulator spring is in there or not.

I do realize that the car is better off shifting for itself. That is why I went to the trouble to tune the WOT shift point. And the tranny shifts great at the track. I am not looking for the tranny to shift exactly at 5,800 when manually going to second. Just respond quick enough that the car doesn't nose over and hit the limiter.

But on the street playing around, I can't give it full throttle until it gets up a little speed. You know, roll into the throttle as the tires will hold it. But that requires a manual shift to second so that it doesn't short shift at part throttle as I roll into it.

So my choice is to either hit the throttle with the selector in 2 and the tranny will short shift because it is at part throttle. I guess I can't get it to full or near-full throttle quick enough. Or hit it with the selector in 1 and then shift to 2 as I get the thottle to the floor, but that is going to cause the tranny to hold in low too long. I probably move the lever to 2 somewhere around 4,000 or so.

So stopping the drum is key, huh? Any tips there?
Posted By: John_Kunkel

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 07:44 PM


When the trans shifts 1-2 automatically the rear band isn't involved, when you manually shift 1-2 the rear band is involved; the band release time is the difference in the two shifts.

If throttling back slightly eliminates the delay, the TP linkage can be shortened.
Posted By: JohnRR

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/17/14 11:58 PM

Quote:

The tranny has the rigid (not flex) band, and the rev limiter is set at 6,500. I believe the lever is a 4.2. I don't remember if the accumulator spring is in there or not.

So stopping the drum is key, huh? Any tips there?



What material is on the band ?

Also in a way stopping the drum is key because that is the shift, no magic other than it has to happen.

Maybe John K. can explain how the rear servo releasing the rear band is connected to the front servo applying the band , if the 2 are connected , or mutually exclusive of each other ?
Posted By: lewtot184

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/18/14 12:32 AM

when i went to the transgo tf2 kit my upshifts were way too high. the only way i could bring them down was to back off the kickdown/throttle pressure adjustment.
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/18/14 01:22 AM

The band material is not Kevlar. But I am not sure other than that.

I can certainly back the kick-down linkage some. I was hoping to keep it where it is, because the low speed shifts are good and the WOT shift is right where I need it.

I may try that tomorrow and see if there is a sweet spot between where the low speed shift point is now and where it ends up if I can get the manual shift point to co-operate.
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/18/14 01:29 AM

Can much be done to get the band to release quicker in this case? Rear band, right?
Posted By: John_Kunkel

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/18/14 06:37 PM

Quote:

Maybe John K. can explain how the rear servo releasing the rear band is connected to the front servo applying the band , if the 2 are connected , or mutually exclusive of each other ?



When a manual 1-2 shift is initiated the manual valve shuts off fluid pressure to the rear servo but the spring pressure returning the piston makes the servo a momentary de facto pump and the pressure it exerts on the 1-2 shift valve delays the actual upshift.

Mopar realized this after a several years and a redesigned 1-2 shift valve (3410886) was introduced in '70 but there can still be some delay because of the channel size in the transfer plate. Some transfer plates have a deeper channel which speeds return flow.

The heavy rear servo return spring included in the TF-2 kit (OP didn't state which TransGo kit he had) helps reduce the lag as will drilling a small hole in the rear servo piston. (I use a #40 drill)
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 12:59 AM

It has the TF-2 kit. I will pull the pan and rear servo and make sure that the heavier spring is there. And I can drill the piston, too.

Is the #40 drill the largest that should be used or is it a starting point? In order to clean up the 2-3 overlap, I ended up pulling the valve body 3 times. I tried a .010-.015 smaller orifice each time till it cleared up. Could I do the same thing with the rear piston? Start with the #40 drill bit and go up .010 or so at a time till the shift responded?
Posted By: JohnRR

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 02:46 AM

Quote:

It has the TF-2 kit. I will pull the pan and rear servo and make sure that the heavier spring is there. And I can drill the piston, too.

Is the #40 drill the largest that should be used or is it a starting point? In order to clean up the 2-3 overlap, I ended up pulling the valve body 3 times. I tried a .010-.015 smaller orifice each time till it cleared up. Could I do the same thing with the rear piston? Start with the #40 drill bit and go up .010 or so at a time till the shift responded?



What year is the trans ? If pre 70 maybe get the valve John mentioned and possibly tweak the passage, or switch to the later VB ??

Drilling the hole bigger and bigger till you fix the not really a problem may cause a problem ... allowing the band to slip in reverse, reverse doesn't have the sparg helping to hold the drum ...

Just a thought .
Posted By: lewtot184

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 04:10 AM

i think the problem with the tf2 kit is the heavy throttle pressure spring. i'm using a stock 4600rpm governor and mine absolutely will not upshift at WOT unless the throttle pressure adjustment is backed way off. i also have excessive 1-2 bind up at low throttle pressure, i think this winter i'll take the heavy spring out and then see what kind of difference there is.
Posted By: sparcy

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 05:50 AM

just had that problem with my 727 1-2 seemed to wind out too much for me . I have a tf 2 I have the lokar cable for t v my brother owns a tray shop he said drop the pressure a little and its working fine .
Posted By: JohnRR

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 05:59 AM

Quote:

just had that problem with my 727 1-2 seemed to wind out too much for me . I have a tf 2 I have the lokar cable for t v my brother owns a tray shop he said drop the pressure a little and its working fine .



Unless you made changes to the Lokar setup it's the problem , it is not designed to work properly on a Mopar.
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 04:53 PM

Quote:

Quote:

It has the TF-2 kit. I will pull the pan and rear servo and make sure that the heavier spring is there. And I can drill the piston, too.

Is the #40 drill the largest that should be used or is it a starting point? In order to clean up the 2-3 overlap, I ended up pulling the valve body 3 times. I tried a .010-.015 smaller orifice each time till it cleared up. Could I do the same thing with the rear piston? Start with the #40 drill bit and go up .010 or so at a time till the shift responded?



What year is the trans ? If pre 70 maybe get the valve John mentioned and possibly tweak the passage, or switch to the later VB ??

Drilling the hole bigger and bigger till you fix the not really a problem may cause a problem ... allowing the band to slip in reverse, reverse doesn't have the sparg helping to hold the drum ...

Just a thought .



It's a post 70 tranny. And I expect to find the heavier Trans-Go spring in the rear servo.

If I back off the kick-down linkage, it will affect the part throttle shift point and likely, the WOT shift point as well. I would prefer to try to avoid that.

I will try drilling the piston as John suggested and see if that clears up the delay. If it doesn't, it doesn't seem that experimenting with enlarging the hole further has a big down side. I don't use reverse very much and can monitor any issues that may be introduced. Besides, the mod is easily reversible.

Ideally, I would hope to address the delay issue without impacting the shift points. If the choice would be that or a soft reverse, then the soft reverse would be the lesser of two evils. For me.

Any thoughts?
Posted By: JohnRR

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 06:48 PM

None , you have already decided on the fix. Let us know how it works out.
Posted By: John_Kunkel

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/19/14 09:58 PM


I wouldn't go any larger than the #40 drill, risks bleeding off too much pressure and making the rear band ineffective.

As to the throttle pressure, backing off the linkage might alter the shift points in auto but at least it would upshift in manual.

The 1-2 shift valve governor plug I mentioned was introduced in '70 but not on all transmissions...the improved version is on the left in the pic below.

Attached picture 8305565-1-2GovernorPlugs.JPG
Posted By: DaveRS23

Re: Can I fix the delayed 1-2 manual shift on my 727? - 10/20/14 01:04 AM

Had to pull the valve body in order to get the rear piston out. Didn't have a #40 bit, so I used a 3/32, which is about .004 smaller. The Trans-Go spring and the little spacers were in place.

Then, as I got ready to put the valve body back in....surprise.... I notice that the valve body is stamped "68". What the ?!?!?
So I go to the stash and pull out one stamped "73'. Tomorrow, I'll swap the shift kit into the "73" valve body. That may deal with the 1-2 delay and I get part throttle kick down to boot.

John, I'll double check that shift valve while I am in there. Thank you so much for taking the time to share your hard earned knowledge.

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