727 Gains RPM Issue
#3055723
07/04/22 09:00 AM
07/04/22 09:00 AM
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Joined: Jan 2003
Posts: 3,831 N.E. Ohio
6bblFLASH
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N.E. Ohio
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Trying to help out a friend. NSS/MW car,10.70s 4.10gear. 493in wedge Last year it would occasionally gain RPM about the 1,000ft mark. Jump from 6,200 to nearly 7,000...car would slow 5 to 8 hundredths. Had trans gone thru by a GOOD trans guy and fellow MW racer. Only thing he found was some slippage on 3rd clutch. Refreshed and back in. Got worse. Ordered a new converter 9.5". Car picked up 60ft....but now gains RPM even more frequently. Pulled the trans again...teardown...no damage or evidence whatsoever. Is totally unpredictable, but he says it seems more frequent as it gains temperature...so installed bigger cooler and a gauge. Never gets past 170. I thought it sounded like it is not keeping the converter full..IE. emptying the pan. Been through all the usual things..fuel pressure/volume ..ignition...shifter. Ideas???
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: sr4440]
#3055737
07/04/22 10:41 AM
07/04/22 10:41 AM
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Joined: Jan 2003
Posts: 3,831 N.E. Ohio
6bblFLASH
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Not sure. Probably Type F
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: J_BODY]
#3055748
07/04/22 11:13 AM
07/04/22 11:13 AM
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Joined: Jan 2003
Posts: 3,831 N.E. Ohio
6bblFLASH
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Is this per data recording? No...tach goes up ...car noses over.
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: sr4440]
#3055749
07/04/22 11:14 AM
07/04/22 11:14 AM
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Joined: Jan 2003
Posts: 3,831 N.E. Ohio
6bblFLASH
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What transmission fluid is he using?
Joe Type F from NAPA
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: MR_P_BODY]
#3055750
07/04/22 11:17 AM
07/04/22 11:17 AM
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Joined: Jan 2003
Posts: 3,831 N.E. Ohio
6bblFLASH
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If you have had the trans looked at a couple of times with nothing wrong, start looking elsewhere Agreed...but what else will gain RPM and lose acceleration together?
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: 6bblFLASH]
#3055817
07/04/22 12:29 PM
07/04/22 12:29 PM
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Joined: Jan 2003
Posts: 25,785 Rio Linda, CA
John_Kunkel
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I'm thinking the transmission guy is missing something awry in one of the clutches or the pump. Deep pan or shallow?
If the VB allows a line pressure gauge tap, a gauge plumbed into the cockpit might show a pressure drop at top end. If the center tap on the case is blocked, a gauge at the front servo will work.
The INTERNET, the MISinformation superhighway
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Re: 727 Gains RPM Issue
[Re: MR_P_BODY]
#3055825
07/04/22 12:43 PM
07/04/22 12:43 PM
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Posts: 3,831 N.E. Ohio
6bblFLASH
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Does this car have RPM limiters of any nature.. if so try to borrow some others... or get new ones (not sure if NSS cars use them) I'm sure it has a MSD chip for max RPM. I will find 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: 6bblFLASH]
#3055828
07/04/22 12:44 PM
07/04/22 12:44 PM
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Posts: 3,831 N.E. Ohio
6bblFLASH
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He is going to install another transmission and see what happens. So we'll see what happens.
I'll update when he gets results Thanks everyone....
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: 6bblFLASH]
#3055984
07/04/22 09:47 PM
07/04/22 09:47 PM
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Joined: Mar 2011
Posts: 3,075 Michigan
A727Tflite
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Trying to help out a friend. NSS/MW car,10.70s 4.10gear. 493in wedge Last year it would occasionally gain RPM about the 1,000ft mark. Jump from 6,200 to nearly 7,000...car would slow 5 to 8 hundredths. Had trans gone thru by a GOOD trans guy and fellow MW racer. Only thing he found was some slippage on 3rd clutch. Refreshed and back in. Got worse. Ordered a new converter 9.5". Car picked up 60ft....but now gains RPM even more frequently. Pulled the trans again...teardown...no damage or evidence whatsoever. Is totally unpredictable, but he says it seems more frequent as it gains temperature...so installed bigger cooler and a gauge. Never gets past 170. I thought it sounded like it is not keeping the converter full..IE. emptying the pan. Been through all the usual things..fuel pressure/volume ..ignition...shifter. Ideas???
What do you mean he saw slippage on 3rd gear clutch? What did he see exactly. Any issues with change in the stall speed or 60’? If you have a spare valve body I would try that first.
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Re: 727 Gains RPM Issue
[Re: DoubleD]
#3056107
07/05/22 09:46 AM
07/05/22 09:46 AM
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Joined: Mar 2011
Posts: 3,075 Michigan
A727Tflite
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take a look at the lines to the trans cooler - are they a soft braided or a rubber line - you might be sucking one closed - also look at the cooler itself junk inside can act like a valve restricting flow
Also could be the valve body acting up - or the shifter is not aligned perfectly Both cooler lines are under pressure at all times when not in park.
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3056125
07/05/22 09:54 AM
07/05/22 09:54 AM
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Joined: Jan 2003
Posts: 2,296 NE Ohio
DoubleD
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take a look at the lines to the trans cooler - are they a soft braided or a rubber line - you might be sucking one closed - also look at the cooler itself junk inside can act like a valve restricting flow
Also could be the valve body acting up - or the shifter is not aligned perfectly Both cooler lines are under pressure at all times when not in park. I don't disagree - but pressure and flow are two different things in a hydraulic system
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Re: 727 Gains RPM Issue
[Re: A727Tflite]
#3056513
07/06/22 02:36 AM
07/06/22 02:36 AM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
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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
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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