440 GTX 727 trans/ Car won't move after it sits for a few days

[V_TastyTacos_V]

Can one assume that if these cars were used daily, like years back when they were "just" cars, that this wouldn't happen?

One of my cars drains back, the other three don't, all original '69 and one '64. I've only owned old Mopars since the '80s, and I can't remember having this problem, except for the one I have now I mentioned, but I remember people talking about it. It might have to do with the seal rings on the reaction support wearing? I'm just guessing.

 

[Darrah]

I always thought people were nuts when they said their 727 had converter drainback. I never had an issue with the multitude of cars I used to own, but now my '71 Road Runner and '74 W200 both drain back within a day or two. Guess I finally stopped getting lucky with trans that didn't do it.

 

[toolmanmike]

Normally the more you run them you don't notice it. I have a 2003 Dakota that does it periodically.

Exactly. I had 2 98 Dakotas. One did it every time and the other one never did. I never had an old Mopar do it until my 70 Swinger.

 

[turbine68rt]

Yes, but the pressure goes from 5psi in Park to 55psi in Neutral. That's why you check fluid in Neutral, when it's actually being pumped.

The point in question was whether or not there was fluid being pumped in park vs. neutral. The answer is both, between 5-30 psi in park and 55 psi in neutral, both following the same basic circuit paths.

 

[turbine68rt]

True, but the hydraulic circuit route is different in park.

They are basically identical. The line and converter pressures are higher in neutral.

 

[Photon440]

They are basically identical. The line and converter pressures are higher in neutral.

Yes, because of different circuits.

 

[turbine68rt]

Yes, because of different circuits.
View attachment 1862681

Show us where the circuits differ.

 

[66 Sat]

 

[turbine68rt]

The circuits themselves remain the same.

 

[Photon440]

The circuits themselves remain the same.

If you note that the slide valve is in a different position, and then look at the legend to see that the pressures are lower in park...

Hard to read, but in Park the converter pressure is 5-30 while in neutral it is 30-55. If it happens to be at the low end (5psi) in park, that's where your slow fill will come from.

 

[turbine68rt]

Correct, there's no need to have full converter pressure in park with no load. I have a 68 & 69 fsm with the same diagrams.