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what engine speed in 80mph?
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mopar666
Posted 2015-10-28 4:12 PM (#493448)
Subject: what engine speed in 80mph?


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Posts: 16

Hi!

What rpm does your engines have with powerflite or tourqueflite transmission?

Mine 59 dodge with powerflite makes 4000 rpm in 50 mph.
I have a week memory It was 2800 rpm before I rebuild the engine, and guess something is wrong with my gearbox.
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jimntempe
Posted 2015-10-28 5:22 PM (#493454 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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sounds like it's stuck in low.
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Rebels-59
Posted 2015-10-28 5:32 PM (#493458 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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Yep sounds like it isnt changing up to 2nd gear, My 59 Dodge with powerflite revs around 2500rpm at 55-60mph
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GregCon
Posted 2015-10-28 6:35 PM (#493465 - in reply to #493458)
Subject: Re: what engine speed in 80mph?



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It's also possible you have 8.93:1 gears in the rear end
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mopar666
Posted 2015-10-29 11:52 AM (#493517 - in reply to #493448)
Subject: RE: what engine speed in 80mph?


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Posts: 16

I have jacked it up and drive it with the rear wheels free, and she goes from low to drive. If I drive on low at 2500rpm, and then go to drive, it shifts and the speedometer is showing a higher speed at 2500rpm. Tryed to adjust the kickdown linkage and bands and it still the same. And checked the pressures in the transmission to, no problem there. The car have been standing still in some mounts. The only thing I done is changed the oil (dexron III) before I started driving with the car again.
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wayfarer
Posted 2015-10-29 11:53 AM (#493518 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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What are you using for a tachometer?
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mopar666
Posted 2015-10-29 12:16 PM (#493519 - in reply to #493518)
Subject: Re: what engine speed in 80mph?


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Posts: 16

I´ts some universal for 8cyl. the guy who owned the car before me installed it. the speedometer shows the right speed. But the tacometer shows 4000rpm in 50, and the engine screams like a angry bull..
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wizard
Posted 2015-10-29 12:56 PM (#493525 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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Don't force the car up to 50 mph until you found out why it doesn't shift to second gear. Check the throttle linkage and also the pushbutton cable, refer to the work shop manual.
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Rebels-59
Posted 2015-10-29 1:16 PM (#493527 - in reply to #493519)
Subject: Re: what engine speed in 80mph?



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mopar666 - 2015-10-29 4:16 PM

I´ts some universal for 8cyl. the guy who owned the car before me installed it. the speedometer shows the right speed. But the tacometer shows 4000rpm in 50, and the engine screams like a angry bull..


If it is screaming at 50mph, then it has it be in 1st gear, as i believe you can drive upto 65mph in 1st on a powerflite

I wouls select Low gear and drive it upto 40mph and then shift into Drive, you should deffo feel it up change at that speed confirming the gearbox is shifting.
Failing that if it does shift up, then the Clutches must be slipping

.
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Powerflite
Posted 2015-10-29 1:30 PM (#493530 - in reply to #493519)
Subject: Re: what engine speed in 80mph?



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How do you know the speedometer is correct? It could have the wrong speedometer gear in the trans or maybe the speedometer isn't working up to spec.

But if the speedo and tach are indeed correct; the only other possibility is that you have some serious slipping inside the trans to get such large rpms without moving it faster. Even the 2800rpm number is probably too high.
You can calculate what the engine rpm is based on your car's parameters like this:

Engine RPM = Speed (MPH) * Trans Gear*Rear Gear*1056 (=12in/ft*5280ft/mile* / 60min/hr) / Tire diam(inches)*Pi
In order to get 2800 rpm at 50mph in final drive gear, you would need to have a 4.56:1 rear gear set with 27in tires. I doubt that is what you are running, but is it right?

RPM= 50mph*1*4.56*1056/(27in*3.1416)=2840rpm

To get 4000 rpm at 50mph is just impossible without having a very bad transmission or a wrong tachometer/speedometer. But if the trans is indeed slipping that badly, don't drive it. It would be causing serious damage inside it. I assume that you checked the trans fluid?
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mopar666
Posted 2015-10-29 1:44 PM (#493533 - in reply to #493448)
Subject: Re: what engine speed in 80mph?


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It shifts. Had it jacked up and drove it with the wheels lifted from the ground. Tried low at first then pushed in the drive.. The drive gear kicks in, and speedometer rises to a higher speed than it does at same rpm in the low gear. Accelerate gently up the speed, no k.d, still in the drive gear and still the engine runs faster then it should.
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57chizler
Posted 2015-10-29 1:45 PM (#493534 - in reply to #493448)
Subject: RE: what engine speed in 80mph?



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If the problem started after an engine removal I'd look at the TP linkage adjustment....it might have been altered.
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mopar666
Posted 2015-10-29 1:56 PM (#493539 - in reply to #493530)
Subject: Re: what engine speed in 80mph?


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Posts: 16

thanks everyone for try to help me! Its my first fl car.

It runned at 2800rpm in 50mph before i rebulit the engine. this problem started when I started driving the car again. I only changed oil in the gearbox before the first start, havent touched it more then that.
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60 Finatic
Posted 2015-10-29 4:12 PM (#493553 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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Vacuum leak? My experience with my first car way back when and I don't know if that is valid with a PowerFlite....
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Beltran
Posted 2015-10-29 9:29 PM (#493592 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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So you had the engine apart and out of the vehicle I assume. What about the torque converter? Did you have it out? Did you check the fluid with the engine warmed up and in neutral? There is quite a bit of fluid in the TQ so you need to check it again after the initial fill.

If it makes two forward shifts and it's a Powerflight 2 spd then that's all there is. If it is a Torqueflite then you have one more gear to go and this problem would make sense. What is your push button configuration?
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57chizler
Posted 2015-10-30 1:46 PM (#493649 - in reply to #493534)
Subject: RE: what engine speed in 80mph?



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Temporarily disconnect the TP linkage at the transmission lever and see if it will upshift.
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ttotired
Posted 2015-10-30 6:10 PM (#493670 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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I am with chizler on this, dis connect the kick down lever (TP Linkage? a new term for it for me)

Running it with the wheels in the air isnt much of a test, the wheels/trans are under no load

You could load it a bit with the brakes, but hard to judge the load and not really nice for your brakes

Be unusual for a trans to go faulty just sitting there

I do not think the oil change itself would be a problem, but re check the oil level again

Only other thing I can think of is the pump drive sleeve (stuff between the engine and torque converter) may be damaged when the engine went in?

This could give you unloaded drive, but slip when loaded, but I think this is very unlikely

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57chizler
Posted 2015-10-31 3:25 PM (#493732 - in reply to #493670)
Subject: Re: what engine speed in 80mph?



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ttotired - 2015-10-30 3:10 PM

I am with chizler on this, dis connect the kick down lever (TP Linkage? a new term for it for me)


TP= Throttle Pressure

You're probably not aware of my one-man campaign to discontinue the use of the term "kickdown linkage". The term implies that the linkage is only for "passing gear" like Phords and Chebbies and leads many uninformed souls to leave it disconnected...thus burning up the trans.
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jimntempe
Posted 2015-10-31 7:23 PM (#493751 - in reply to #493448)
Subject: Re: what engine speed in 80mph?



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Disconnecting the TV (throttle valve) linkage can damage the transmission. It can result in the pressures being too low and letting the clutches/bands slip because with it disconnected the transmission thinks the engine is at idle speed and only needs low pressure. WHen you drive that way it may upshift but then slip due to the low pressure.
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57chizler
Posted 2015-11-02 2:04 PM (#493969 - in reply to #493751)
Subject: Re: what engine speed in 80mph?



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Disconnecting the linkage temporarily for testing purposes will cause no damage unless the throttle is hammered repeatedly.
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mopar666
Posted 2015-11-11 12:23 PM (#494907 - in reply to #493448)
Subject: RE: what engine speed in 80mph?


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Posts: 16

A little update.

Took of the pan and the gearbox is real clean on the inside. no parts or other thing in the pan either.
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