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Skyhoist sx57 has power to controls and hydraulic pressure. Will not move or respond

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Having some sort of a fan issue going on...


my guess is you dont know the radiator fan rules.
its different on each of 3 engines
I have the 3.7L in same car, same year, but is WK yours is XK
the larger passenger compartment with bigger engine.
i have the FSM (SM) factory service manual.
so will post the words out of it , its free to read, posted 300+ time here. and no more posts, im going dark....lol
chapter 7 covers both engine.
5.7:
the 5.7 uses hydraulic fan (not electric motors but uses hydraluic motors, off ps pump)
so is the PS, assist ok and no noises from it.?
first the quotes in cht.7
5.7L ENGINE The 5.7L hydraulic cooling fan is integral
to the fan shroud and is located between the radiator
and the engine.
The power steering pump supplies the hydraulic fluid
and pressure to rotate the cooling fan blade, while the
electrical part of the fan is controlled by the FCM.
The hydraulic fan drive (motor) consists of the three
major following components:
² Steering flow control valve
² Fan control valve
² Two stage G-rotor hydraulic drive
The hydraulic fan and drive is not serviceable. Therefore
any failure of the fan blade, hydraulic fan drive or
fan shroud requires replacement of the fan module
because the fan blade and hydraulic fan drive are
matched and balanced as a system and servicing
either separately would disrupt this balance.
end quote now the rules
HYDRAULIC FAN STRATEGY
The hydraulic radiator cooling fan is controlled by the FCM. A PWM (Pulse With Modulated) signal from the JTEC
controls the fan speed. There are four inputs to the FCM that determine what speed percentage of fan is required
by the vehicle. These inputs are:
² Engine Coolant Temperature
² Transmission Oil Temperature
² A/C System Pressure
By monitoring these three parameters, the FCM can determine if cooling airflow is required. If airflow is required, the
FCM will slowly ramp up (speed up) the fan speed until the parameter(s) are under control. Once the temperature
HYDRAULIC FAN FLUID FLOW CIRCUIT
1 - POWER STEERING RESERVOIR
2 - POWER STEERING PUMP
3 - HYDRAULIC FAN DRIVE ASSEMBLY
4 - FAN BLADE
5 - HYDRAULIC FAN CONTROL SOLENOID
6 - POWER STEERING OIL COOLER
7 - STEERING GEAR
WK ENGINE 7 - 35
or pressure is reduced to within operating parameters the fan will ramp up, ramp down, or hold its speed to maintain
the temperature / pressure requirements.
NOTE: Even if the FCM is not requesting fan on operation the fan blade will usually spin between 100 and
500 RPM when the vehicle is at idle. This is due to a controlled minimum oil flow requirement through the
fan drive motor.

so is it still broke, or just a learning curve
its not simple at all.
in fact all 2005 up GC are complex fan controls
every one,
using tables to decide need, and speed.
on all modern jeeps.

Apr 10, 2016 | 2010 Jeep Commander 5.7

1 Answer

Is there an adjustment to increase hydraulic power on Komatsu pc35mr-2 mini excavator? Or is there a sensor that is responsible for relationship between engine rpm and hydraulic operation?


you assumption is right
the pump is operating at idle as at full rpms and is controlled by pressure relief valves
When demand for pressure is low the valves will be partially opened and will operate when the pressure is reduced ( ram valve is moved)
Higher rpms maintain the pressure for faster ram operation
I would suggest that you have the system pressure tested by a service centre as it could be a malfunctioning valve (solenoid) or a failing pump

Mar 28, 2015 | Mini Cars & Trucks

1 Answer

1979 case 2090 does not move , no hydraulics, no steering nothing


Yeh I think your on the right track with the hydraulic pump, if it's power shift as well it stands to reason that the pump has failed, you can fit a guage to the coupling on the rear of the tractor and it will tell you if the hydraulics are working to pressure, hope this helps

Jan 21, 2015 | Cars & Trucks

1 Answer

The shifter is stuck, unable to move, the car starts. flat brake and shifter button of heavily. but I can not move


sounds like your brake system has no hydraulic pressure which means it wont engage the lockout controls on the shifter find the hydraulic leak. repair, fill, bleed, braking system. then it should change gears and start.

Jan 20, 2015 | 2003 Cadillac CTS

1 Answer

What causes a mini excavator (Yanmar B27) on rubber tracks to shudder and shake ( bunny hops) when first moving forward or reverse? Would worn track rollers produce this effect? Thx


probably not--This sounds like uneven pressure from the hydraulic pump or problems with the drive motors. Check that the hydraulic oil filter is in good condition (not blocked) and have the pressure in the hydraulics checked.. Have the hydraulic controls checked for correct operation. (if electric controls check for voltage problems to the solenoids and if manual check for control valve problems)

Oct 05, 2014 | Cars & Trucks

1 Answer

Transmission seems to shift in and out of overdrive


Check the transmission fluid level. The sensor for speed may be tripping or not tripping causing the overdrive to engage or disengage at a particular speed. ---
Understanding the Hydraulic Control System The hydraulic pressure used to operate the servos comes from the main transmission oil pump. This fluid is channeled to the various servos through the shift valves. There is generally a manual shift valve, which is operated by the transmission selector lever, and a shift valve for each up shift the transmission provides.
Most automatic transmissions are electronically controlled; electrical solenoids are used to control the hydraulic fluid. The shift solenoids are regulated by an electronic control module. Shift timing is regulated through sensor feedback information provided to the electronic controller.
On older transmissions there are two pressures that control the shift valves. One is the governor pressure which is affected by vehicle speed. The other is the modulator pressure which is affected by intake manifold vacuum or throttle position. Governor pressure rises with an increase in vehicle speed, and modulator pressure rises as the throttle is opened wider. By responding to these two pressures, the shift valves cause the up shift points to be delayed with increased throttle opening to make the best use of the engine's power output.
Older transmissions also make use of an auxiliary circuit for downshifting. This circuit may be actuated by the throttle linkage, vacuum that actuates the modulator, or by a cable or solenoid. It applies pressure to the downshift surface on the shift valve or valves.
The transmission modulator also governs the line pressure, used to actuate the servos. In this way, the clutches and bands will be actuated with a force matching the torque output of the engine.

Oct 18, 2010 | 1996 Chevrolet Tahoe

1 Answer

1998 dodge dakota 5.2L V8, I have 2nd and 3rd gear only with automatic transmission.


In the 1998 Dodge Dakota 5.2L V8 if you have only 2nd and 3rd gear with the auto transmission, the solenoid inside for shifting down to 1st gear is not functioning correctly.

A complete transmission rebuild is indicated in this situation, where all of the clutches and solenoids that are bad are replaced.

This involves tearing down the transmission after removing it from the vehicle, and; rebuilding it from the ground up.

Try to find a local transmission repair shop where they are certified to do this kind of work.
----
A basic description of the problem follows:
Servos/Accumulators The servos are hydraulic pistons and cylinders. They resemble the hydraulic actuators used on many other machines, such as bulldozers. Hydraulic fluid enters the cylinder, under pressure, and forces the piston to move to engage the band or clutches.
Servo operation tccs7015.gif

The accumulators are used to cushion the engagement of the servos. The transmission fluid must pass through the accumulator on the way to the servo. The accumulator housing contains a thin piston, which is sprung away from the discharge passage of the accumulator. When fluid passes through the accumulator on the way to the servo, it must move the piston against spring pressure, and this action smoothes out the action of the servo.
Hydraulic Control System The hydraulic pressure used to operate the servos comes from the main transmission oil pump. This fluid is channeled to the various servos through the shift valves. There is generally a manual shift valve, which is operated by the transmission selector lever, and a shift valve for each up shift the transmission provides.
Most automatic transmissions are electronically controlled; electrical solenoids are used to control the hydraulic fluid. The shift solenoids are regulated by an electronic control module. Shift timing is regulated through sensor feedback information provided to the electronic controller.
On older transmissions there are two pressures that control the shift valves. One is the governor pressure which is affected by vehicle speed. The other is the modulator pressure which is affected by intake manifold vacuum or throttle position. Governor pressure rises with an increase in vehicle speed, and modulator pressure rises as the throttle is opened wider. By responding to these two pressures, the shift valves cause the up shift points to be delayed with increased throttle opening to make the best use of the engine's power output.
Older transmissions also make use of an auxiliary circuit for downshifting. This circuit may be actuated by the throttle linkage, vacuum that actuates the modulator, or by a cable or solenoid. It applies pressure to the downshift surface on the shift valve or valves.
The transmission modulator also governs the line pressure, used to actuate the servos. In this way, the clutches and bands will be actuated with a force matching the torque output of the engine.
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Aug 17, 2010 | 1998 Dodge Dakota

1 Answer

03 dodge caravan, 105,000 miles, 2.4L transmission will shift in all gears but will not go into overdrive from 3rd gear. when it does shift to overdrive i try to speed up on the gas and it shifts back into...


I'm afraid that the transmission's O/D solenoid malfunctioning or kick down cable may be misadjusted if so equipped.

looking at a rebuilt transmission if you plan to keep the Caravan.

Or, alternatively, could get a low mileage transmission from a salvage yard and have it installed.

----
Servos/Accumulators The servos are hydraulic pistons and cylinders. They resemble the hydraulic actuators used on many other machines, such as bulldozers. Hydraulic fluid enters the cylinder, under pressure, and forces the piston to move to engage the band or clutches.
Servo operation tccs7015.gif

The accumulators are used to cushion the engagement of the servos. The transmission fluid must pass through the accumulator on the way to the servo. The accumulator housing contains a thin piston, which is sprung away from the discharge passage of the accumulator. When fluid passes through the accumulator on the way to the servo, it must move the piston against spring pressure, and this action smoothes out the action of the servo.
Hydraulic Control System The hydraulic pressure used to operate the servos comes from the main transmission oil pump. This fluid is channeled to the various servos through the shift valves. There is generally a manual shift valve, which is operated by the transmission selector lever, and a shift valve for each up shift the transmission provides.
Most automatic transmissions are electronically controlled; electrical solenoids are used to control the hydraulic fluid. The shift solenoids are regulated by an electronic control module. Shift timing is regulated through sensor feedback information provided to the electronic controller.
On older transmissions there are two pressures that control the shift valves. One is the governor pressure which is affected by vehicle speed. The other is the modulator pressure which is affected by intake manifold vacuum or throttle position. Governor pressure rises with an increase in vehicle speed, and modulator pressure rises as the throttle is opened wider. By responding to these two pressures, the shift valves cause the up shift points to be delayed with increased throttle opening to make the best use of the engine's power output.
Older transmissions also make use of an auxiliary circuit for downshifting. This circuit may be actuated by the throttle linkage, vacuum that actuates the modulator, or by a cable or solenoid. It applies pressure to the downshift surface on the shift valve or valves.
The transmission modulator also governs the line pressure, used to actuate the servos. In this way, the clutches and bands will be actuated with a force matching the torque output of the engine.
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Aug 09, 2010 | 2003 Dodge Caravan

1 Answer

I have a 1997 Dakota 121,000 miles and replace the transmission 15,000 miles ago. I bought this from Ebay. Worked fine till now and it won't shift into low when you stop and doesn't shift to over drive...


prev.gif next.gif DRIVE TRAIN
  • Servos/Accumulators The servos are hydraulic pistons and cylinders. They resemble the hydraulic actuators used on many other machines, such as bulldozers. Hydraulic fluid enters the cylinder, under pressure, and forces the piston to move to engage the band or clutches.
    Servo operation tccs7015.gif

    The accumulators are used to cushion the engagement of the servos. The transmission fluid must pass through the accumulator on the way to the servo. The accumulator housing contains a thin piston, which is sprung away from the discharge passage of the accumulator. When fluid passes through the accumulator on the way to the servo, it must move the piston against spring pressure, and this action smoothes out the action of the servo.
    Hydraulic Control System The hydraulic pressure used to operate the servos comes from the main transmission oil pump. This fluid is channeled to the various servos through the shift valves. There is generally a manual shift valve, which is operated by the transmission selector lever, and a shift valve for each up shift the transmission provides.
    Most automatic transmissions are electronically controlled; electrical solenoids are used to control the hydraulic fluid. The shift solenoids are regulated by an electronic control module. Shift timing is regulated through sensor feedback information provided to the electronic controller.
    On older transmissions there are two pressures that control the shift valves. One is the governor pressure which is affected by vehicle speed. The other is the modulator pressure which is affected by intake manifold vacuum or throttle position. Governor pressure rises with an increase in vehicle speed, and modulator pressure rises as the throttle is opened wider. By responding to these two pressures, the shift valves cause the up shift points to be delayed with increased throttle opening to make the best use of the engine's power output.
    Older transmissions also make use of an auxiliary circuit for downshifting. This circuit may be actuated by the throttle linkage, vacuum that actuates the modulator, or by a cable or solenoid. It applies pressure to the downshift surface on the shift valve or valves.
    The transmission modulator also governs the line pressure, used to actuate the servos. In this way, the clutches and bands will be actuated with a force matching the torque output of the engine.
  • Jul 14, 2010 | Dodge Dakota Cars & Trucks

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