727 Problem

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ricks70dart

ricks70dart

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I have a 70 Dart 340 with 727.Had the transmission rebuilt about 3000 miles ago,The problem I'am having is after it sits a day or so I go to back out of garage and when I put in reverse it takes 30 seconds or so for It to move like it has to build pressure then after that its fine other then that the trans works fine.I have heard this is called morning sickness.What causes this and can it be fixed in the car.Its not a big deal but would like to know what my options are Thanks..
 
Sonnax makes a manual valve to help that problem, can drop valve body and replace without removing transmission
 
Convertor is draining when sitting. When cold most will put it in neutral, wait a minute or rev it a bit, and then put it in gear.
 
ricks70dart said:
Would like to know were the problem is so I can remedy it. Is the problem in the Valve body?
Click to expand...
I have the exact same issue on my rebuilt transmission as well and the simple solution for me to just start it in neutral and wait a minute and its good to go. Not sure about exact permanent solution but as REPLICARACER suggested seems like a resolution to look into.

Jake
 
ricks70dart said:
Would like to know were the problem is so I can remedy it. Is the problem in the Valve body?
Click to expand...

Refer to your first answer (#2) (replicaracer43.
Transgo also offers a revised Manual Valve in their shift kits..
 
ricks70dart said:
I have a 70 Dart 340 with 727.Had the transmission rebuilt about 3000 miles ago,The problem I'am having is after it sits a day or so I go to back out of garage and when I put in reverse it takes 30 seconds or so for It to move like it has to build pressure then after that its fine other then that the trans works fine.I have heard this is called morning sickness.What causes this and can it be fixed in the car.Its not a big deal but would like to know what my options are Thanks..
Click to expand...

Here's the deal.
"Morning sickeness" really only applies to transmissions that have old rubber seals that need to warm up before they flare out and seal.
In your case the converter is likely draining back into the trans when it sits caused by sloppy fitting converter bushing in the pump and worn pump gears.
The loose tolerances let the fluid run back into the trans.
(If the rest of the rebuild was done right)
If it wasn't the problem could be worn sealing ring surfaces, bushings and/or they didn't replace the lip seal on the reverse servo.

Most builders won't replace a pump if it isn't actually damaged but just normally worn some.

Putting the thing in neutral for a couple of seconds allows fluid to circulate unlike in park, so the new manual valve mentioned does allow fluid circulation in park and fills the converter back up as soon as the engine starts.

The REAL actual fix is to put in a new pump with new pump gears, new bushing and depending on converter hub wear a new converter.

(Just put the new valve in the valve body and let it go at that.):D

The TF2 shift kits come with that valve in case you are interested.
 
Even with a pump in tolerance, and new bushings, the converter will still drain back, deal with the crank in neutral method, or install the valve I posted.
 
I just start mine in neutral. The neutral circuit is different than park, and the converter will fill while you are idling it for a short time
 
replicaracer43 said:
Even with a pump in tolerance, and new bushings, the converter will still drain back, deal with the crank in neutral method, or install the valve I posted.
Click to expand...

Just slower.
I can hit the key and drop it in reverse all in about 3 seconds and it's backing up.
Different story if they sit for a few days. :D
 
Can drill a hole in valve body, i dont recall where. It refills torque and you can check fluid level in park.
I will see if i can find the info.
 
I agree with post #2. I seem to remember that the issue is in the valve body, maybe the metal dividing plate and a check valve. I don't think that the issue is related to the front pump. A good tranny man should know about this common problem.
 
Murray said:
I agree with post #2. I seem to remember that the issue is in the valve body, maybe the metal dividing plate and a check valve. I don't think that the issue is related to the front pump. A good tranny man should know about this common problem.
Click to expand...

Mine does the same thing, all the parts mentioned are new or replaced. It doesn`t bother me at all. My 'bought new" 2002 dodge quadcab did it too. The factory manual said it was normal , and not to worry. I didn`t worry about it for 15 years, and was still fine when I traded for my 2014 ram.
 
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