727 shifting issue

[74gtx]

Hi Everyone, I have read through as many old posts as I could find. My issue is at wot my transmission wont shift into second gear unless i let off the throttle and stab it again. To my surprise a 440 can take close to 7000 rpms! Thanks in advance. Mike (1974 roadrunner gtx 440/727) Other then wot the transmission shifts and drives very well. It does seem to shift a bit early though.

 

[lewtot184]

too much throttle pressure. back the adjuster off at the carb a few turns.

 

[Yatzee]

Linkage settings are out of spec or shifter body needs some attention. There also existed a bit of an issue with shift overlap if the bands were improperly adjusted which you'll have to investigate. I used to have a similar issue until I installed a TCI shifter body which gave me positive, quick shifts and stopped convertor drain back.

 

[74gtx]

Thank you both very much for the replies. I will try to re adjust the linkage this weekend. What you are saying is the detent is being forced back to far correct? Mike

 

[74gtx]

I tried readjusting the kickdown this weekend. I still have the same issue with 1-2 shift at WOT. Now it shifts way to soon through all gears and it slips from 2-3. I also found whoever owned the car before had it so tight that the throttle would not fully open. Does anyone have any ideas where I should look next? Thanks, Mike

 

[mopar 3 B]

Take it to an transmission shop and have the govener pressure checked.

 

[miller]

While your there, have 'em check, or re-adjust the bands, too!

 

[74gtx]

Thanks, That is my next step. Unfortunately its hard to find an honest shop in my area. Hopefully I'll find one. Mike

 

[383man]

You really need to get it to a good trans shop. If you loosen the throttle pressure to much it will shift way to soon and can slip as the trans throttle pressure (which is controlled by the rod from the trans to the carb) has alot to do with line pressure also as it goes to the pressure regulator and helps to control the line pressure. It sounds like throttle press was to high and now its to low. I have seen techs overhaul transmissions and still have a fast shift and slipping on the shift all because the throttle pressure was off and to low. Best to get it to someone who knows transmissions well. Good luck , Ron

 

[janbanan]

You really need to get it to a good trans shop. If you loosen the throttle pressure to much it will shift way to soon and can slip as the trans throttle pressure (which is controlled by the rod from the trans to the carb) has alot to do with line pressure also as it goes to the pressure regulator and helps to control the line pressure. It sounds like throttle press was to high and now its to low. I have seen techs overhaul transmissions and still have a fast shift and slipping on the shift all because the throttle pressure was off and to low. Best to get it to someone who knows transmissions well. Good luck , Ron

I´m not sure if I got it right but...I have the same problem with shifting manually from first to second, could it be I have adjusted throttle pressure to "hard". I have Lokar wire. There was a big play on valve body lever and I made sure to have it adjusted all the way in on full throttle.I have overhauled my 727 and everything is updated and specs are right. The only thing I didn´t look at was the valvebody. Maybe someone have messed around with it?

 

[74gtx]

Thanks for all of the replies. I'm going to study up on these the best I can and try to resolve it myself. So far everyone only wants to sell me a new tranny. I still think its alright just needs to be adjusted properly, If a normal person drove it it would be just fine i'm sure. I will let you all know what I find. Thanks, Mike

 

[SlinktRR]

Thanks for all of the replies. I'm going to study up on these the best I can and try to resolve it myself. So far everyone only wants to sell me a new tranny. I still think its alright just needs to be adjusted properly, If a normal person drove it it would be just fine i'm sure. I will let you all know what I find. Thanks, Mike

Is this the stock kickdown linkage? If you have a non-stock carb you may not be able to adjust the throttle valve enough. I like the bouchillon kit, easy to adjust and can be used with any carb. Definitely not a new transmission that is ridiculous. Get underneath on the drivers side and see how much movement you get with the throttle valve when the pedal is to the floor. Then reduce the travel by adjusting the kickdown and see how it affects your shift points.

 

[miller]

Another way to set the kickdown linkage...

Un-hook the throttle return springs off the throttle arm, so you have free, and full movement. Assuming you have the slotted type adjuster end on the kickdown linkage. Push the kickdown rod fully back, and hold the carb throttle arm full open (wot). The adjuster slot on the kickdown should have a small gap, between the throttle arm, and the 'end' of the slot. If not, adjust the kickdown end until it does. Book gives a drill size for stock clearance there. Main thing it keeps the kickdown linkage from 'bottoming', or binding.

Next, check forward movement (at idle), by putting the throttle arm at idle. The kickdown linkage slot should easily fit on the throttle arm, with free play, no binding, with the kickdown linkage full forward. If good, re-hook the springs, and try it.

 

[EARLY B]

the length of the lever on the trans has to match the linkage used. The length of the lever should be about 2" center to center with the use of the edelbrock adapter at the carb.

 

[miller]

That's why I mentioned checking both ends of linkage travel. All has to somewhat fit, allowing pretty much full sweep of the kickdown lever at the trans. That, and no binding at either end.

To make kickdown, and throttle pressure work right, carb linkage, kickdown rod, and lever has to work together, no matter what kind of hook-up you have.

 

[74gtx]

I couldn't check it out closer today because it started snowing here. My garage is to small to work in. The linkage does feel kind of notchy when you move it by hand. I drilled a hole in the arm last weekend to get the carb to open the secondaries. I know the engine is from 69 so maybe the tranny is too. The linkage is not adjustable near the carb. (other than drilling holes) Thanks, Mike

 

[Yatzee]

Miller is spot on on the setup. To check for functionality you almost need two people, one up top and one below. With the throttle wide open the lever at the trans should be all the way back but this is just a starting point. If your shifts are too soon you have to create a bit more slack in the linkage as you pressure is coming on too soon. It's the reverse for late shifts. Increase or decrease linkage length a very little at a time ( it need only be done at the carb ). Your shift times will indicate which way to adjust. It's best done on a country road with the air cleaner removed. Stop, adjust and drive. Note the shift timing with every adjustment. You may have to do it several times as this is a touchy adjustment.
You can adjust the bands yourself but the low/reverse ( at the back of the tranny ) is best left a little looser than the spec calls for or you'll end up in "shift overlap " territory where both bands stay engaged for a split second and create a hard shift. 727's are bullet proof transmissions, very simple in construction and brutes for power. Screw the repair shops, anyone with half a brain and $300 can rebuild their own at home with instructions off You Tube.

 

[miller]

Notchy? Should be a smooth movement all the way, getting just spring resistance, last third of moving to the rear. All your looking at inside the trans pan, is a spring loaded piston, that's being pushed in. IF it's not smooth movement, could mean there's 'trash' in the valve/shift body, where that piston (and all the others) are.

No rod adjustment at the carb? Can you describe the kickdown linkage you have? Or a pic would be better.

If the kickdown/throttle pressure is off too much, for too long...could be working toward a burned trans!!!

 

[74gtx]

Hi Miller, I dont know how to post pictures but my linkage has a flat piece of metal with a notch for the carb and a hole (now several) that attaches to the bar that runs to the trans. I assume the only way to adjust mine is near the transmission at this point. The engine is out of a 69 and I have no idea what year the tranny is. Now that you mentioned the piston I wonder if its screwed up from being pushed to hard as the linkage was holding the carb to only opening half way. Thanks, Mike

 

[miller]

Hiya, 75gtx...hard to say on the kickdown linkage, without having a look. Can say it's real easy to mix/match Mopar engines/trans, where things will work. If you have one, I'd suggest getting into the service manual...it will show the various kickdown linkage set-ups, giving an idea what you have, right or wrong.
Right now, there's no telling. Stock carb?

On the 'piston' for the kickdown/throttle pressure...piston only moves about 1/2", or so, spring loaded so when rod is off it, the piston is moved back to 'rest'. Yes, it should move easily...yes, it could be hung. Only way to get to it...drop the trans pan.

Also in the service manual, is info on the trans, rebuilding and adjustments. You would be doing good to crack the book, and get a better understanding about what your looking at. Besides the kickdown piston need to move freely, there's an adjustment for the piston stop...band adjustment...