Re: 727 Gains RPM Issue
[Re: Cab_Burge]
#3056546
07/06/22 08:21 AM
07/06/22 08:21 AM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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[quote=DoubleD
Both cooler lines are under pressure at all times when not in park.
isn't it around 30 lbs. or less pressure(maybe 15 to 20 Lbs. ) to the tranny cooler My earlier reply was directed at the statement that the cooler lines, if rubber, could be sucked closed. They can’t because they always see pressure. You are correct, the lines normally see 15-30 psi but varies. It would be interesting to see how much flow makes it to the trans for guys that mount their cooler at the back of the car.
Last edited by Transman; 07/06/22 08:21 AM.
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3056550
07/06/22 08:36 AM
07/06/22 08:36 AM
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Joined: Jan 2003
Posts: 2,299 NE Ohio
DoubleD
top fuel
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top fuel
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[quote=DoubleD
Both cooler lines are under pressure at all times when not in park.
isn't it around 30 lbs. or less pressure(maybe 15 to 20 Lbs. ) to the tranny cooler My earlier reply was directed at the statement that the cooler lines, if rubber, could be sucked closed. They can’t because they always see pressure. You are correct, the lines normally see 15-30 psi but varies. It would be interesting to see how much flow makes it to the trans for guys that mount their cooler at the back of the car. while maybe the word sucked is not the best choice - lines fail - if you have worked around hydraulic systems long enough you will see a soft line failure - like a brake hose that fails and blocks flow but does not burst - what happens is the hose breaks down and the oil gets between the layers and literally can collapse the line closed - like a valve
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Re: 727 Gains RPM Issue
[Re: moparx]
#3056850
07/06/22 06:53 PM
07/06/22 06:53 PM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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"It would be interesting to see how much flow makes it to the trans for guys that mount their cooler at the back of the car. " could you explain, please ? i don't quite understand, as i'm kind of a dunce at times. thanks ! Hydraulic system “friction”. Think of electric circuits, the measurement for resistance.
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3057143
07/07/22 01:50 PM
07/07/22 01:50 PM
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Joined: Aug 2003
Posts: 43,285 Bend,OR USA
Cab_Burge
I Win
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I Win
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Bend,OR USA
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"It would be interesting to see how much flow makes it to the trans for guys that mount their cooler at the back of the car. " could you explain, please ? i don't quite understand, as i'm kind of a dunce at times. thanks ! Hydraulic system “friction”. Think of electric circuits, the measurement for resistance. I'm thinking steel or aluminum will have less internal friction, resistance, to fluid flow than neoprene or rubber. lines. I'm not sure about PTFE, Teflon lined hoses internal friction One way to find out is by doing a flow test in gear
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 727 Gains RPM Issue
[Re: Cab_Burge]
#3057232
07/07/22 05:32 PM
07/07/22 05:32 PM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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"It would be interesting to see how much flow makes it to the trans for guys that mount their cooler at the back of the car. " could you explain, please ? i don't quite understand, as i'm kind of a dunce at times. thanks ! Hydraulic system “friction”. Think of electric circuits, the measurement for resistance. I'm thinking steel or aluminum will have less internal friction, resistance, to fluid flow than neoprene or rubber. lines. I'm not sure about PTFE, Teflon lined hoses internal friction One way to find out is by doing a flow test in gear A novel idea, a cooler flow test.
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3057413
07/08/22 01:27 PM
07/08/22 01:27 PM
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Joined: Sep 2003
Posts: 19,589 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
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my old noggin is beginning to understand now ! thank you guys for helping me out ! the electrical circuit analogy made it click. also, the steel/aluminum tubing vs hose. with the cooler flow test idea, i'm thinking comparing stacked plate to tube and fin ? if so, would/should the internals of the cooler be how much larger [size wise] than the in/out lines to the transmission ?
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Re: 727 Gains RPM Issue
[Re: moparx]
#3057420
07/08/22 02:14 PM
07/08/22 02:14 PM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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my old noggin is beginning to understand now ! thank you guys for helping me out ! the electrical circuit analogy made it click. also, the steel/aluminum tubing vs hose. with the cooler flow test idea, i'm thinking comparing stacked plate to tube and fin ? if so, would/should the internals of the cooler be how much larger [size wise] than the in/out lines to the transmission ? Actually you want to compare “ delta”. The difference between the output flow at the front cooler line fitting versus the return line entering at the trans. Everything in between has a direct effect on the return volume. Pressure is a useless measure for this. The less that comes back could have a negative impact on geartrain durability and a direct impact on stall.
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Re: 727 Gains RPM Issue
[Re: moparx]
#3057697
07/09/22 03:44 PM
07/09/22 03:44 PM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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is there an inline "flow meter" type of gauge one could use to check this ? i still enjoy learning things i don't know, even though i'm old. Most of the transmissions I tested (727,46/47/48) produced about a quart of flow at idle in less than 10 seconds, in neutral, at approx. 65-75 degrees. That’s at the front cooler line fitting, one by the bell housing.
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3059769
07/16/22 11:07 PM
07/16/22 11:07 PM
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Joined: Jan 2003
Posts: 3,842 N.E. Ohio
6bblFLASH
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Works fine with the spare transmission in the car. So on to the next problem.
70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas 9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ! 2013 StickShift Challenge Winner@ Mopar Nationals!
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Re: 727 Gains RPM Issue
[Re: AndyF]
#3059877
07/17/22 10:35 AM
07/17/22 10:35 AM
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Joined: Jan 2003
Posts: 3,842 N.E. Ohio
6bblFLASH
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Yep. Could be a casting issue. The case is probably going to be thrown out.
70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas 9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ! 2013 StickShift Challenge Winner@ Mopar Nationals!
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Re: 727 Gains RPM Issue
[Re: SportF]
#3060061
07/18/22 12:11 AM
07/18/22 12:11 AM
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Joined: Mar 2006
Posts: 9,871 MI, usa
dvw
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Why would the rear clutch pack slip only in high gear? If it was slipping why wouldnt the frictions and steels show it? The rear clutch never begins its engagement with the input shaft spinning. So it is subjected to minimal slippage. If for some reason the trans was loosing pressure in 3rd only it should show in the front clutch. As far as the case itself. The passageway to the forward clutch feed isnt much over a 1" long. Pretty easy to see if its cracked. Its my feeling if there is no clutch damage that possibly the converter fill is being restricted or bleeding fluid internally. That would raise rpm and not show signs of slipage. Doug
Last edited by dvw; 07/18/22 12:22 AM.
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