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What could be the 727 slipping?


Well-Known Member
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1:20 PM
Feb 18, 2010
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Any trans techs please, I have got my motor running really good, good enough that after pushing her hard for a while the RPMs began outrunning the trans. She got me home, and put a 8'' puddle under her. Got her out today and thought I could just warm her up easy, but about a block into the drive she began slipping again. I am betting torque conv, but dont want to pull and put conv in and it be something else. Safe to just do conv by what I described or could it possibly be clutches, or are they pretty bullit proof? Trans fluid level is fine so what would be your suggestions please? And yes, I would like to have 4K$ for a manual too, but need to make this work for a while.
The converter is probably the last thing. It's probably a band or clutches. What gear(s) was it slipping in? Only when hot? Any flare on shifts? Only slipping at a certain rpm? Did you actually check fluid level? Need way more info.
Is the kickdown/throttle pressure linkage hooked up and adjusted properly?
What exact gears does it slip. Does it flare on shifts? Does it engage drive or reverse normally or is it slow to engage or bang into gear?
Guys, let me check out some of the things you want to know, as in if it goes into drive and reverse like it should. I may try to drive it again but was not wanting to get hauled home as it seemed to be getting worse, and when and if it goes............I will check more out tomorrow. Thanks
It may be as simple as fluid loss. You said it had a puddle under it when you got home. Fill it up and pop it off and check it for leaks. Might be something stupid like a leaking trans line. If it gets low on fluid, it will slip. Simple as that. Don't start thinkin doom and gloom until you've checked the simple things first.
If the wrong lubricity oil has been used, it could cause an automatic to slip sometimes.
Got some info now. I just drove her pretty hard back and forth in front of the house, ( so I wouldnt have to walk as for ). I will give you a brief history of how I got to where I am now. She was a new rebuilt and cherry max wedge but I could not get her to run right, as some of you may remember. I took her down to answer " what is in her?" I didnt know so I pulled her down, put a hydrolic cam, eddie 28 to line up the carbs, and alum heads. I have Lokar linkage but....have not hooked up the kick down cable yet, " OK dumb ^%$, you burned up drive." I will say that before anyone else does. Now as to the answers to the questions from above, I think it only is slipping in drive after she is hot, I can push button to 1st or 2nd and she doesnt seem to have a problem. The fluid was a pint low when I first started her today, and a pint over full after hot. I shot the trans with a temp gun and she was 210 at the hottest point but the pan only shot at 160 degrees. Once she slipped a little, I pushed to 2nd and she went right in. Got home and hit drive / reverse and she wanted to go in reverse when I hit neutral but after setting for a sec she shifted all buttons as should. Backed her on the lift, shot the temps and came in to share my story.
Get the linkage hooked up. It MIGHT not be burnt up in drive yet. The linkage regulates fluid pressure. If the pressure is low in drive, it will slip. Since drive has the least leverage to move the car, any pressure loss will show up there first. If you restore the pressure loss by hooking up and adjusting the linkage correctly, it might be ok. I consider the linkage as important as tires. You wouldn't take off down the road on three tires, so why the hell did you drive it incomplete? That was majorly stupid.
Thank you for the swift kick in the &^%. Hopefully, and out of ignorance, I did not think that there was anything to the kick down except to go to second gear. Now, if you would, how do I adjust the kick down cable? Do I set it to kick in just off of full throttle, and is it all in, or nothing, as in, does it open the valve a little even if it doesnt kick down to second. Just not sure how to set it up or if it does anything else besides kicking down to second. Thanks for the help.
Hay, we all do stupid stuff. I wrote the book. So it's a cable and not mechanical linkage? Either way, makes no difference. Here is how you do it. Block the gas pedal all the way on the floor (with the car not running, of course.). Now adjust the cable, or linkage so that with the throttle all the way open, the transmission lever the linkage or cable is attached to is all the way towar the REAR of the car. In other words, all the way to the REAR of the lever's travel. Then drive it. If you feel like it holds the shifts too long, then back off a little at a time....but that should get it right.

Chrysler Torqueflites MUST have that throttle pressure linkage installed. It's not just for kickdown. As the throttle is opened, more power is transferred to the transmission. The clutch packs are held together by hydraulic fluid pressure. Normally, as the throttle is opened, the throttle pressure linkage pushes the lever back on the transmission and increases the hydraulic line pressure equal to the amount of throttle opening. If that linkage is not hooked up, then there is no line pressure increase and nothing to keep the clutch packs holding the additional power as the engine RPM increases and the transmission will slip, starting in the highest gear first. Usually, when one starts slipping, the damage is done. Every now and then though, I've gotten lucky and stopped the slipping by hooking up linkage somebody forgot to connect. It's rare that happens, so get ready to tear it down.
Set it up to be all but 1/8 of an inch back at full throttle. And I think mine has 1/2 - 3/4 inch play before it starts to pull the cable. I also had to put a small return spring on the pressure lever, because the stock one on the original stuff was gone. I hope I am getting this right.

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Thats not fair, Rusty types with more than one finger. lol
Thanks, now the light bulb is coming on by learning from my mistakes. Now it is possible that I get to learn how to rebuild a trans. Hopefully I get a second chance, the fluid still looks new and doesnt smell burned. Sad to think though, if I get a second chance, I still probably have created a weak link now. Well, next drive the cable will be hooked up as close to yalls recomendations. Fingers crossed, but hey, what the heck, if I have to drop another 12-1500.00 its just a Mopar thing, but dont let my wife find out about it.
Heads up to anyone out there faced with a no throttle pressure linkage situation. If you have to drive a car and it isnt hooked up, crawl under the car and tie the lever back about 3/4 of the way. increased line pressure at low rpm is far better than low pressure at high rpm. Of course having the linkage hooked up is the best policy. Or get a manual valve body so you dont have to worry about the linkage.