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Fluid control in a 727 pan #2093112
06/16/16 06:38 PM
06/16/16 06:38 PM
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New York
polyspheric Offline OP
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polyspheric  Offline OP
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Perhaps I'm overlooking something obvious, but should we be concerned about uncovering the pump pick-up on high-G acceleration?
When the front wheels come up, the fluid rushes backward and stands up on the back wall of the pan just like in the engine oil pan.
How does this not cause an air bubble to enter the pick-up, which will cause momentary loss of line pressure when that slug of fluid passes through the valve body, etc?

If there's been a prior discussion on this, please point me to it?
Thanks.


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Re: Fluid control in a 727 pan [Re: polyspheric] #2093115
06/16/16 06:45 PM
06/16/16 06:45 PM
Joined: Nov 2011
Posts: 2,154
Its a TRAP!
DARTH V8Я Offline
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DARTH V8Я  Offline
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Its a TRAP!
Always thought there's enough fluid in the pan not to get uncovered short of going upside down.


When it takes more than a sweet mullet to prove you rule at the trailer park..
Re: Fluid control in a 727 pan [Re: polyspheric] #2093144
06/16/16 07:42 PM
06/16/16 07:42 PM
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Posts: 916
MB,CAN
PC-CHARGER Offline
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I've seen some fabricated pans that have a rear baffle for just this reason. That combined with a deep pan and extended pickup would minimize the chance of uncovering the pickup.

Re: Fluid control in a 727 pan [Re: PC-CHARGER] #2093154
06/16/16 07:57 PM
06/16/16 07:57 PM
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Posts: 43,190
Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
Originally Posted By PC-CHARGER
I've seen some fabricated pans that have a rear baffle for just this reason. That combined with a deep pan and extended pickup would minimize the chance of uncovering the pickup.
iagreeI have a older Pro Trans SS/AH 727 with a B&M aluminum deep pan on it that has a baffle welded onto the back side going up to the pickup to keep tranny fluid around the pickup no matter the angle of the motor and trans thumbs scope work I've never done that to a deep Mopar brand steel pan, maybe my cars don't leave hard enough to worry about that confused Maybe I should work

Last edited by Cab_Burge; 06/16/16 07:58 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Fluid control in a 727 pan [Re: polyspheric] #2093200
06/16/16 09:54 PM
06/16/16 09:54 PM
Joined: Oct 2007
Posts: 4,206
New York
polyspheric Offline OP
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polyspheric  Offline OP
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New York
Thoughts from Brian P in response to my post at Speed Talk:

"Suspicions (nothing more)
The specified fluid level is high enough, and the orientation of the pick-up is such that the pick-up doesn't pull in air under that situation.
In a drag-race start, the clutches needed for 1st gear are already engaged and the torque converter is already full of fluid, and the lock-up clutch (if there is one) is not going to be engaged at that moment. What it means is that there is actually not much demand for fluid volume at that moment. For the clutches to disengage, not only would the pump have to be sucking air but there would also have to be demand for sufficient fluid at that moment - for example, if the trans controls were commanding one of the other clutches to engage.
By the time the trans controls are commanding some other clutch to engage (demanding fluid), the violent forces of the start aren't present any more."


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