Transmission issue
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Joined: Dec 2021
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From: Senstobia ms
Transmission issue
I have a 98 xlt 4x2 ranger. It was shifting really funny it would go into drive and reverse you could feel it engage and it would move slowly high rpm. If you turn overdrive on it will shift through the gears just fine. So I pulled pan changed all solenoids just in case changed filter and fluid old fluid looked fine to me. Put it back together added fluid not problem was still present that day. Went out the next morning cranked it and put in gear drive fine like nothing was wrong. My question could I still have an issue?
Welcome to the forum
Well its possible but you will just need to wait and see
All automatics run on Fluid Pressure, always have and always will
90psi pressure, minimum, is need for Foward
140psi for Reverse, this is why automatics often lose Reverse first when there is a pressure issue, needs a higher pressure to engage
In the old days there were spring and ball valves, that would open and close when pressure was high and then low and that shifted gears
Solenoids replaced those and a computer opened and closed valves based on speed and engine load to change gears
Shifting in to D or R is a mechanical engagement, solenoids are not used, but a leaking or stuck open solenoid could cause lower pressure so slow engagement
The fluid pressure is generated by a pump inside front of transmission, connected directly to torque converter, so pump spins at engine RPMs, and so increasing engine RPMs would increase pump speed and the pressure it can generate
The pump sends the fluid/pressure to the Valve Body, obviously were the valve are located, lol
The valves then route the fluid/pressure to the Clutches and bands(brakes) for the selected gears as needed
Any gasket leaks or seal leaks in the valve body would, of course, lower the pressure in the system
Changing the solenoids wouldn't fix leaks, but could have let a valve close that was stuck open, valves are all spring loaded
On a 1998 Ranger trans there would be an EPC(electronic pressure control) solenoid, and that could have been the issue as well
When you drain fluid and then refill, AIR can get trapped inside valve body and clutches and bands so that could have been why it worked OK the next day, all the air had bubbled out of the passages
All automatics have at least 2 external pressure test points, which you can use to diagnose issues, need a gauge that goes up to 400psi to be on the safe side
Just as a heads up
Automatics have WAY TOO MANY inter-dependent systems to diagnose specifically for most problems, they are harder to diagnose than engine issues for sure
Well its possible but you will just need to wait and see
All automatics run on Fluid Pressure, always have and always will
90psi pressure, minimum, is need for Foward
140psi for Reverse, this is why automatics often lose Reverse first when there is a pressure issue, needs a higher pressure to engage
In the old days there were spring and ball valves, that would open and close when pressure was high and then low and that shifted gears
Solenoids replaced those and a computer opened and closed valves based on speed and engine load to change gears
Shifting in to D or R is a mechanical engagement, solenoids are not used, but a leaking or stuck open solenoid could cause lower pressure so slow engagement
The fluid pressure is generated by a pump inside front of transmission, connected directly to torque converter, so pump spins at engine RPMs, and so increasing engine RPMs would increase pump speed and the pressure it can generate
The pump sends the fluid/pressure to the Valve Body, obviously were the valve are located, lol
The valves then route the fluid/pressure to the Clutches and bands(brakes) for the selected gears as needed
Any gasket leaks or seal leaks in the valve body would, of course, lower the pressure in the system
Changing the solenoids wouldn't fix leaks, but could have let a valve close that was stuck open, valves are all spring loaded
On a 1998 Ranger trans there would be an EPC(electronic pressure control) solenoid, and that could have been the issue as well
When you drain fluid and then refill, AIR can get trapped inside valve body and clutches and bands so that could have been why it worked OK the next day, all the air had bubbled out of the passages
All automatics have at least 2 external pressure test points, which you can use to diagnose issues, need a gauge that goes up to 400psi to be on the safe side
Just as a heads up
Automatics have WAY TOO MANY inter-dependent systems to diagnose specifically for most problems, they are harder to diagnose than engine issues for sure
Last edited by RonD; Dec 13, 2021 at 05:31 PM.
Thread Starter
|
Member
Joined: Dec 2021
Posts: 4
Likes: 0
From: Senstobia ms
Thanks
Welcome to the forum
Well its possible but you will just need to wait and see
All automatics run on Fluid Pressure, always have and always will
90psi pressure, minimum, is need for Foward
140psi for Reverse, this is why automatics often lose Reverse first when there is a pressure issue, needs a higher pressure to engage
In the old days there were spring and ball valves, that would open and close when pressure was high and then low and that shifted gears
Solenoids replaced those and a computer opened and closed valves based on speed and engine load to change gears
Shifting in to D or R is a mechanical engagement, solenoids are not used, but a leaking or stuck open solenoid could cause lower pressure so slow engagement
The fluid pressure is generated by a pump inside front of transmission, connected directly to torque converter, so pump spins at engine RPMs, and so increasing engine RPMs would increase pump speed and the pressure it can generate
The pump sends the fluid/pressure to the Valve Body, obviously were the valve are located, lol
The valves then route the fluid/pressure to the Clutches and bands(brakes) for the selected gears as needed
Any gasket leaks or seal leaks in the valve body would, of course, lower the pressure in the system
Changing the solenoids wouldn't fix leaks, but could have let a valve close that was stuck open, valves are all spring loaded
On a 1998 Ranger trans there would be an EPC(electronic pressure control) solenoid, and that could have been the issue as well
When you drain fluid and then refill, AIR can get trapped inside valve body and clutches and bands so that could have been why it worked OK the next day, all the air had bubbled out of the passages
All automatics have at least 2 external pressure test points, which you can use to diagnose issues, need a gauge that goes up to 400psi to be on the safe side
Just as a heads up
Automatics have WAY TOO MANY inter-dependent systems to diagnose specifically for most problems, they are harder to diagnose than engine issues for sure
Well its possible but you will just need to wait and see
All automatics run on Fluid Pressure, always have and always will
90psi pressure, minimum, is need for Foward
140psi for Reverse, this is why automatics often lose Reverse first when there is a pressure issue, needs a higher pressure to engage
In the old days there were spring and ball valves, that would open and close when pressure was high and then low and that shifted gears
Solenoids replaced those and a computer opened and closed valves based on speed and engine load to change gears
Shifting in to D or R is a mechanical engagement, solenoids are not used, but a leaking or stuck open solenoid could cause lower pressure so slow engagement
The fluid pressure is generated by a pump inside front of transmission, connected directly to torque converter, so pump spins at engine RPMs, and so increasing engine RPMs would increase pump speed and the pressure it can generate
The pump sends the fluid/pressure to the Valve Body, obviously were the valve are located, lol
The valves then route the fluid/pressure to the Clutches and bands(brakes) for the selected gears as needed
Any gasket leaks or seal leaks in the valve body would, of course, lower the pressure in the system
Changing the solenoids wouldn't fix leaks, but could have let a valve close that was stuck open, valves are all spring loaded
On a 1998 Ranger trans there would be an EPC(electronic pressure control) solenoid, and that could have been the issue as well
When you drain fluid and then refill, AIR can get trapped inside valve body and clutches and bands so that could have been why it worked OK the next day, all the air had bubbled out of the passages
All automatics have at least 2 external pressure test points, which you can use to diagnose issues, need a gauge that goes up to 400psi to be on the safe side
Just as a heads up
Automatics have WAY TOO MANY inter-dependent systems to diagnose specifically for most problems, they are harder to diagnose than engine issues for sure
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