Help ! 727 Drive in neutral

I have a '63 pushbutton 727 (so it has front and rear pumps, B&T output and PB cable shift with separate park). I rebuilt it and since this was my first auto tranny I was very careful and followed the FSM and Tom Hand's book during the process. Air test was good. Trans is now installed with no driveshaft and I'm testing it with the engine before I drop the body on frame. The problem is I have drive in neutral. I've adjusted the shift cable every way possible first by the FSM for push buttons, then FSM for console sift, by neutral safety switch with test light, and finally by disconnecting the cable at the push button and slowly moving the cable with the engine running from reverse to drive and I never do find neutral. The output shaft turns and cannot be stopped. Reverse does work as do D, 1 & 2.

So now I have done a pressure test with these results: At idle (around 750) monitoring line pressure and kick down release in neutral I have 0 & 0. In D I have 65 line and 0 KDR (line goes to 90 with throttle shaft at WOT). In 2 I have 65 line and 0 KDR. In 1 I have 65 line and 0 KDR. In R I have 0 & 0. I really don't know what these mean but I'm pretty sure these results are not good. What do I need to look for? I do have another valve body I could clean up and try. Hoping the trans internals are ok but that's why I'm testing it before I put the body on.

Your help is greatly appreciated (and needed)!

Are the wheels just turning slowly? Can you stop them by hand? If so thats pretty normal. If the forward clutch was applied incorrectly in N/P, then it would actually be in 1st gear. If the kickdown band was to tight it would be in 2nd gear. In either case reverse would be bound up and the other forward gears wouldn't function. If all gears function and it shifts correctly you should be fine.
Doug

That is gonna be one nice ride when finished!

This ^^^^^ the output will turn if there is no driveshaft and the wheels are not on the ground , I had the same thing happen with a duster I had a long time ago with the rear tires off the ground , I was able to stop the wheel from turning with my foot.

It's not just costing, it's turning with power, I cannot stop the output shaft from turning (no driveshaft).

I don't see an easy way to stop it without the driveshaft, does the trans have park or does it have a brake drum on the end of it ? If it really is under power then something went in wrong ???

It has park. I try to stop it with a piece of wood against the output B&T flange. It's turning with the same power in D as it does in N. It will slow down in 1 & 2.

I agree something is wrong, just hoping the pressure test results would point me in some direction.

Thanks. I just hope it's finished some day!

1st timers always ask this question, I did myself one time, put it on the ground with wheels and it won't.

BTW beautiful car!

And yes you wont stop it by hand no matter how hard you try. Most cars will move if you pay attention, when you wing them in neutral.

hopefully Kunkel or A727Tflite sees this

Thanks for your reply and I hope you're right! I just want to do as much as possible to ensure it's good before the body makes it a lot more difficult to pull the tranny. I've found charts that show which clutches are engaged, etc. in each selector position, but not one that shows what the pressures should be. I'm hoping someone on here can shed some light on the pressure test.

Like what has been said, not unusual for the output to rotate in neutral.

As for pressure tests, they don’t always reveal an issue. You could have normal pressures and something mechanically wrong with the rear clutch causing the drag but if you followed the book you should be good.



Manual low - pressure on the rear servo and within 3 pounds of line, nothing at the front servo
Second gear - line pressure, nothing at the front or rear servo.
Third gear - line and front servo release should be within 3 pounds of line
Reverse - rear servo only

Make sure you start in manual low and shift manually - you should feel it go from low to 2nd then third.

The fact that Reverse works is a good indicator that there's nothing wrong...if a faulty rear clutch was causing it to drive in Neutral. putting it in Reverse would likely lock up the output shaft. Worst way to test the operation is with no drive train or, even with drive train, on jack stands.

Well, those replys are very encouraging. Thanks to all who replied! I guess the next step is to put the body on the frame. Hopefully I'll be able to road test it someday.

i really like your car !

Thanks!

A very long time ago I had a 63 Plymouth that was originally a Max Wedge car. It still had the original transmission and it would pull itself in neutral when it was cold.

So as others have said, I don't think you have a problem.

The early 727 was notorious for creeping forward in Neutral...the reason was the rear clutch drum where captive fluid would cause enough drag to act like the clutch was partially applied. The fix was to drill a series of holes around the periphery of the drum for trapped fluid to escape from. First introduced in '67.

Thanks for that info. My rear drums are not drilled so that could be the cause. Anyway, I'm putting the body on the frame and won't worry anymore until I do a test drive. That will be a ways off.