Question about GMC Sonoma

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Hello I rebuilt my automatic transmission gear one month ago. I changed all clutches, band, regulator pressure valve, 1st accumulator with the spring which was broken before, torque has been repaired. The gear behaved like new and very smooth the first days. Then It started shifting rough from 1st to 2nd. Now, when stopping the car, I feel the gear like shifting inside, as if it disengages and ingages again. Adding to this, it strted to shift hard from 2nd to 3rd, but not like from 1st to 2nd. Did the spring of the 1st accumulator get bropken again? I put a used one. Can you help for these problems? I would appreciate it much jmjcharbel2003@yahoo.com

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  • GMC Master
  • 3,433 Answers

Hello;
Two questions first. please.
Did you chk the converter sprag?
Is the converter and front pump properly engaged? Thanks, Ned

Posted on Apr 03, 2011

  • mar peter Apr 12, 2011

    Hello

    The converter was cut and done by a specialist. So no intervention from my side.
    I am sure that the the converter and the pump are properly engaged. I checked it before installing the gear

    Thanks a lot

    Peter

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1 Answer

Dodge Ram 3500 skips from 1st to 3rd gear, had rebuild after still the same issue. Any advice?


Governor pressure controls the 1st and 2nd shifts. After that is the 3 and 4 solenoids. you would need to look at the pressure when driving(takes a scanner). pressure is 20 to 30 PSI from 1st to 2nd, depends on acceleration. After that the pressure will jump to 100+ psi. Did you replace the governor solenoid and sensor? They are on the passenger side of the transmission and sit in a block that detaches from the valve body.

Sep 22, 2016 | 2005 Dodge Ram 3500

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Nissan Sentra 2005 lags in changing 1st to 2nd gear


You need to have the systems computer tested for fault codes, that is the very 1st thing that needs to be done. If they rebuilt the transmission for $900 they did not replace very many parts or do a through job, the average cost is more like $2500.00

May 17, 2012 | 2005 Nissan Sentra

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Rebuilt transmission put in 5 months ago, already lost 1st gear does this mean I need to get another transmission


yes or rebuild it agine sometimes you can get a bad band and not know it for 1000 miles. or till it just quit

Aug 01, 2011 | 1998 GMC Jimmy

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I have a 94 k1500 and I'm having transmission problem. the trans was rebuilt less them 2 years but the way i drive it i can understand the trans going bad, i do alot of hunting and fishing witch i have...


I'm sure it does have something to do with the "ECM or something". After all. the transmission is controlled by the ECM. (Actually. it is a PCM "Powertrain Control Module" not an ECM "Engine Control Module").
Here is a list from the service manual for your transmission of the things that can cause slipping in first gear:
**************************************
Forward clutch assembly plates worn.
Porosity or damage in forward clutch piston.
Forward clutch piston inner and outer seals missing, cut or damaged.
Input housing to forward clutch housing O-ring seal missing, cut or damaged.
Forward clutch housing damaged.
Forward clutch housing retainer and ball assembly not sealing or damaged.
Turbine shaft seals missing, cut or damaged.
Valve body accumulator valve stuck.
Valve body face not flat, damaged lands or interconnected passages.
Valve body spacer plate or gaskets incorrect, damaged or incorrectly assembled.
TV cable binding or broken.
Damaged ring grooves on 1-2 accumulator piston.
1-2 accumulator piston seal missing, cut or damaged.
1-2 accumulator cover gasket missing or damaged.
Leak between 1-2 accumulator piston and pin.
Broken 1-2 accumulator spring.
Fourth servo piston installed backwards.
Incorrect oil pressure. Refer to "High or Low Oil Pressure".
*******************************************
To put it simply, you need to begin diagnosis by scanning the PCM for fault codes in an effort to eliminate some of the possibilities. If you are losing all gears, including reverse when this happens, there may be a problem with the pressure regulating solenoid or its circuits. Scanning the PCM just might tell you this. Don't just run out and buy a PCM thinking that it will fix the problem. This is something that has to be DIAGNOSED. Diagnosis MAY lead to PCM replacement, but this is pretty rare.

Jul 30, 2011 | 1994 Chevrolet K1500

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

    4 Answers

    Shifts fine untill it goes into drive and overdrive,dut i can manu shift and let of the gas with alot of rpms it changes


    Do you have any transmission fault codes that may indicate a problem with the OD control solenoid? if you haven't run this test have the system scanned as a 1st step, but based on what u say I think u have a internal hydraulic leak in the OD apply clutch, this will require a tear-down and reseal of the transmission to correct the problem, which means a complete overhaul or install of a rebuilt transmission, which is the best way to go.

    Feb 16, 2010 | Chevrolet Blazer Cars & Trucks

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    2004 silverado tranny acting up starting w/ 2nd gear, revs up at about 1800 rpms like it goes into neutral, reverse and 1st gear work fine, fluid level over full and smells burnt and looks dark, was...


    Burned clutches I know you said they just seviced it but i would take it back if its still under warranty. Just by what you said the tranny is slipping and the burnt smell is an indication of burnt clutches. The rev up is a sure sign its slipping.

    Jan 02, 2010 | 2004 Chevrolet Silverado 1500 Crew Cab

    1 Answer

    Shift solenoid not engaging overdrive which


      The valve body contains six solenoid valves:
    • three PWM solenoid valves (pulse width modulation solenoid valves,
    • two shift solenoid (on/off) valves,
    • one main regulating valve (variable force solenoid).
    The individual clutches and bands are supplied pressure from the PWM solenoid valves and the shift solenoid (on/off) valves and thus the gears are shifted.
    The PWM solenoid valves allow direct actuation of the clutches and bands to ensure extremely smooth gear shifting through precise pressure regulation.
    The shift solenoid (on/off) valves switch the hydraulic path to the clutches and bands, reducing the number of required modulating valves.
    The main regulating valve (variable force solenoid) ensures that sufficient hydraulic pressure is available in all operating conditions.
    PWM solenoid valves 1-3 PWM solenoid valves 1, 2 and 3 control the pressure to the bands and clutches.
    Shift solenoid (on/off) valves 1 and 2 The shift solenoid (on/off) valves switch the different oil passages in the valve body to direct the pressure to the individual clutches and bands.
    The use of the shift solenoid valves are needed for direct actuation of the individual clutches and bands.
    Main regulating valve The main regulating valve (variable force solenoid) controls the required main line pressure for the individual transmission ranges.
    The main line pressure is controlled dependent on the current engine load.
    ----------------------------------------------------------------------------------------------------
    Electronic synchronous shift control (ESSC)
    Control of shift operations
    During a shift operation certain elements are released while others are actuated. Ideally this process takes place simultaneously (synchronously) to avoid jerky gear shifting.
    The time for the shift operation should remain within the time limits provided.
    When the shift operation is controlled conventionally, the pressure build up and reduction at the shift elements are set and defined for ideal conditions (synchronous shifting).
    As there is no way of influencing the control in the event of different levels of wear in the shift elements, when the transmission has been used for a fairly high mileage it is possible that the pressure build up and reduction may no longer be synchronous.
    The result or premature pressure reduction at the element to be switched off is an unwanted rise in the turbine shaft speed as the element to be switched on cannot transmit the input torque.
    The result of delayed pressure reduction at the element to be switched off is an unwanted decrease in the turbine shaft speed as both shift elements transmit the input torque. In the process the torque is transmitted to the transmission housing through internal locking.
    In both cases a **** will be felt during the shift operation.
    In addition, wear in the shift elements leads to a lengthening of the shift operation. Therefore, shifting takes longer when the transmission has accumulated a higher mileage.
    Control of shift operations with ESSC In the 4F27E automatic transmission electronic synchronous shift control (ESSC) is used.
    ESSC monitors the shift operations and is able to adapt to the wear in the shift elements over the life of the transmission.
    This is possible since the shift elements are actuated by modulating valves.
    The system monitors the shift time whether the shift operation is synchronous.
    If the PCM detects a deviation from the stored values for the shift time and synchronization of the shift operation, the pressure build up or reduction is adapted accordingly.
    Throttle position (TP) sensor The TP sensor is located on the throttle body.
    It supplies the PCM with information about the position of the throttle plate.
    It also detects the speed of actuation of the throttle plate.
    The PCM uses the signals for the following functions among other things:
    • to determine the shift timing,
    • to control the main line pressure,
    • to control the torque converter lock-up clutch,
    • for kickdown.
    In case of absence of the TP signal the engine control uses the signals of the MAF and IAT sensors as a substitute signal. The main line pressure is increased and hard shifts may occur.
    Mass air flow (MAF) and intake air temperature (IAT) sensor The MAF sensor is located between the air cleaner housing and the air intake hose leading to the throttle housing.
    The IAT sensor is incorporated in the housing of the MAF sensor.
    The MAF sensor in conjunction with the IAT sensor provides the PCM with the primary load signal.
    The PCM uses the signals for the following functions among other things:
    • to control the shift operations,
    • to control the main line pressure.
    If the MAF sensor fails, the signal of the TP sensor is used as a substitute.
    Crankshaft position (CKP) Sensor The CKP sensor is located on the engine/transmission flange.
    The CKP sensor is an inductive sensor which provides the PCM with information about the engine speed and position of the crankshaft.
    The signal is used for the following functions among other things:
    • to control the torque converter lock-up clutch,
    • to check the torque converter slip,
    • to control the main line pressure.
    No substitute signal is available for the CKP sensor. If the signal is not present, the engine stops.
    Turbine shaft speed (TSS) sensor The TSS sensor is located in the transmission housing over the transmission input shaft.
    The TSS sensor is an inductive sensor which senses the speed of rotation of the transmission input shaft.
    The signal is used for the following functions:
    • to control the shift operations,
    • to control the torque converter clutch,
    • to check the torque converter slip.
    If the TSS sensor fails, the signal of the output shaft speed (OSS) sensor is used as a substitute signal.

    Dec 17, 2009 | 2003 Ford Focus

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