727 shifting issue

[Frank R]

Does anybody have a clue on this...727 transmission will not shift into 3 under full power. the kickdown linkage is set to factory and several tweaks each way to no avail. it shifts 1,2 fine. When holding the pedal down it will not shift if I back of a touch it almost feels like the wheels lock up for a split second then shifts..I am runnig a 440 with a 2400 stall..didn't have the problem with the 383 and stock converter. I call tranny shops and all they tell me is "bring it in" well I kinda feel like they should at least have a clue as to what the problem is before I give them my ride. Frank

[rampage_82]

Did you have a shift kit or governor work done to it? What exactly is your "factory" setting? Just for grins take the kickdown off completely and take it for a short drive and see what your shift points are then, that will tell you if you are having a kickdown or governor issue... Also what type of fluid and what is your fluid level? Also from the locking up feeling, that sounds like a tight band, which isn't releasing in time between shifts..

[John Kunkel]

The need to lift the throttle for a shift means it's a throttle pressure issue.

Is the carb factory or aftermarket? If aftermarket does it have the correct Mopar throttle lever extension?

The "feels like the wheels are locking up" is a separate issue, you're experiencing severe clutch/band overlap.

[Frank R]

No governor work has been done, it does have a shift kit that was installed years ago. When I took the 383 out, I went through the tranny and the only change was to change the stock KD lever to the 5.1. I am running standard fluid with a deep pan. The tranny was carefully taken apart and the clutch plates were changed and of course new seals, no other changes were made to the VB since the trans was working correctly. Not sure where to go from here. In talking to shops I would at least like an explanation that makes some sense before I "bring it in". Not that I'm perfect but I have rebuilt several 727s and 906s and have never had a problem with any of them. Frank

[Frank R]

John, to answer your question I am running a mighty demon and have purchased the carb hardware from Don at FBO. I did go to the Lokar cable kickdown (thought that would help) but I had the same problem with the stock Set up. I should clarify the wheels locking up is at the exact moment I back off and the shift finally occurs. How would I solve the clutch/band overlap and is the pressure issue solved by drilling a small hole in the 3rd vein in the valve body just left of the shiftcock?.

[70AARCuda]

get rid of the 5.0 lever and got to 4.2 or 3.8....that will help

[cudabob496]

I really like the reverse manual valve body on my Cuda. I get to shift it exactly when I want to, depending on the circumstances! And I got to dump all that linkage! Shifts aren't bone-jarring either! Trannys last longer with manual valve bodies I'm told.

[John Kunkel]

I agree with Cuda, the 5.0 lever is well known to aggrevate overlap on the 2-3 shift...a 4.2 or 3.8 (3.8 in your case) would be better.

Drilling the small hole mentioned is for converter charging, nothing to do with the shifts.

The Lokar cable is also contributing to your shift problem, the Lokar setup only works correctly if the travel of the trasnsmission lever matches the travel of the carb lever and they seldom do in stock form. The statement in the OP that "the kickdown linkage is set to factory" doesn't quite agree with the Lokar installation.

The stock linkage with any aftermarket carb has to have the correct throttle lever extension and the Lokar needs to be re-engineered to work correctly on any Torqueflight. Adjusting either one so that the transmission lever is full back at WOT almost always results in late or no WOT upshifts.

[mhenesian]

Hi Frank,

Looks like John Kunkel gave you a good list of things to check !

If you're looking for a brand new valve body for a 727TF, I'd recommend the auto/manual Pro-Street one from Turbo-Action ($260 from Summit Racing, http://www.summitracing.com/parts/TAC-17676/, the owner Paul Forte is a well known MOPAR racer). Perfect shifts every time. Better than the MOPAR valve body that I modified for light bracket racing with Transgo parts. For a very reasonable price and a quality product, why mess around ! It fixed a lot of shift problems, particularly at the track.

Before, our 727TF would hang in 2nd gear at full throttle for around 300+ RPM. Would shift into 3rd on the rev limiter (6300 RPM) which was very annoying. Now, the 2nd to 3rd shift is sharp without any hangup.

The TA-17676 requires the kick down linkage, since it's a forward shift auto/manual valve body. The linkage adjustment doesn't seem to be too critical. At full throttle, the lever should be full back, minus a couple of turns on the threaded adjuster,

Mark

[mhenesian]

Oh, one more thing. The picture in the Summit online catalog is not quite correct. Turbo Action no longer supplies the big spring for the low-reverse band operation. The new instruction sheet from TA no longer mentions the modification. Apparently it causes grief (bent retainer parts) and not much benefit on a dual purpose vehicle. They also recommend a loose low-reverse band adjustment (3 turns instead of 2 turns) and a tight kick down band (1 1/2 turns instead of 2 turns). We used these settings and there is no obvious band overlap, or lockup between shifts,

Mark

[John Kunkel]

Bent retainers are common with the heavy spring in the rear servo but a billet retainer takes care of that. I'd disagree that the spring is "not much benefit", I consider it essential. Loosening the band as a substitute for the heavy spring only invites band/linkage breakage.

[mhenesian]

Thanks John,

I guess changing out the rear servo spring to the heavy duty Turbo Action one - without a heavy duty retainer - probably caused grief to Turbo Action. The heavy duty retainer is an extra cost item ($35 ?), so many customers would just put the old one back in, and have it bend or break ! Either way, Turbo action recommends the 3 turns adjustment on the low reverse band, stock is 2 turns or is my memory failing !

Mark

[cudabob496]

Here's a list of possibilities from my tranny book by Carl Munroe:
low fluid level
throttle linkage adjustment
kickdown band adjustment
line press too high or low
governor malfunction
valve body malfunction
sticking accumulator
broken accumulator rings or spring
malfunctioning clutch or servo
oil pump malfunction
and about 5 other things that I will list if needed.

[John Kunkel]

The problem with running the rear band loose is that it imparts more shock on the band and anchor links, the extra play gives the piston a "longer run" and it slams the parts really hard.

Band/link breakage is a common problem in bone stock units when the band gets loose and is exacerbated with the higher line pressures in performance transmissions...cold line pressure often exceeds 300 psi in Reverse.

[70 net440]

I had some similar issues with my Dart. I think I'm going to go full manual too.

[mhenesian]

I really stand by the Turbo-Action valve body for the 727TF, the auto/manual Pro-Street one ($260, http://www.summitracing.com/parts/TAC-17676/). Very easy install, good instructions, and performance is great for a street /strip vehicle. If you're scarred about the band adjustments, just set them up with the stock specs. I also own two TA torque converters (11" Hemi and 10" race). Turbo Action has never let us down in over 30 yrs of using there stuff,

Mark

[rampage_82]

I know the Manual Cheetah ones have never let us down....