Transmission problem

[steven62882]

I have a 1997 ranger with a 4.0 and a 5r55e transmission. If you put it in reverse or drive it does nothing, but it works in 2nd and low. But if i unhook the wiring harness from the transmission it will move in all gears

 

[RonD]

Reads like you have a seal leaking in a solenoid, it trans fluid level is OK

All automatics run on Fluid Pressure, not a Ford thing, that's just how they all work

Fluid pump(front pump) is connected to torque converter so spins/pumps at engine RPMs
That pressurized fluid goes to the valve body
To get D to engage you need at least 100psi
For R you need 150psi, this is why Reverse often slow to engage or fails first when transmission has a pressure issue

1st will often engage if one-way clutch has failed or pressure is low but D won't

In the old days ball and spring valves were used for auto shifting, and vacuum
Now-a-days a computer is used and then solenoids are used to open and close the valves

The valves engage and disengage clutches and brakes(bands)

If you remove the power(12v) from the solenoids, i.e. unplug 16 pin connector, all the solenoids close, are deactivated
If one was Leaking pressure then enough pressure might return to get D and R working again, but it wouldn't shift(2nd, 3rd, 4th) of course

If this transmission has over 200k miles I would just rebuild it, 250-300k is expected life, unless it has been rebuilt before by a marginal trans shop, then they last 18 months or 20k miles maybe

You can put in a new valve body and see how that works, this can be done without removing the transmission and not a waste of money since new valve body would be needed for a rebuild

If you look for replacement
1997 to 2011 4.0l trans will work as is if 4x4, if 2WD then you will need to swap tail shaft housing, just a few bolts, to get speedometer hook up needed in a 1997, that was removed in 1998 and up transmissions

If rebuilding ALWAYS replace
pump
one-way clutches(sprags)
OD drum
Most places don't do this and trans will fail in 18months usually

 

[steven62882]

Reads like you have a seal leaking in a solenoid, it trans fluid level is OK

All automatics run on Fluid Pressure, not a Ford thing, that's just how they all work

Fluid pump(front pump) is connected to torque converter so spins/pumps at engine RPMs
That pressurized fluid goes to the valve body
To get D to engage you need at least 100psi
For R you need 150psi, this is why Reverse often slow to engage or fails first when transmission has a pressure issue

1st will often engage if one-way clutch has failed or pressure is low but D won't

In the old days ball and spring valves were used for auto shifting, and vacuum
Now-a-days a computer is used and then solenoids are used to open and close the valves

The valves engage and disengage clutches and brakes(bands)

If you remove the power(12v) from the solenoids, i.e. unplug 16 pin connector, all the solenoids close, are deactivated
If one was Leaking pressure then enough pressure might return to get D and R working again, but it wouldn't shift(2nd, 3rd, 4th) of course

If this transmission has over 200k miles I would just rebuild it, 250-300k is expected life, unless it has been rebuilt before by a marginal trans shop, then they last 18 months or 20k miles maybe

You can put in a new valve body and see how that works, this can be done without removing the transmission and not a waste of money since new valve body would be needed for a rebuild

If you look for replacement
1997 to 2011 4.0l trans will work as is if 4x4, if 2WD then you will need to swap tail shaft housing, just a few bolts, to get speedometer hook up needed in a 1997, that was removed in 1998 and up transmissions

If rebuilding ALWAYS replace
pump
one-way clutches(sprags)
OD drum
Most places don't do this and trans will fail in 18months usually

Sounds like a pretty easy change on the valve body think i will give that a try. Thank you so mych

 

[steven62882]

Reads like you have a seal leaking in a solenoid, it trans fluid level is OK

All automatics run on Fluid Pressure, not a Ford thing, that's just how they all work

Fluid pump(front pump) is connected to torque converter so spins/pumps at engine RPMs
That pressurized fluid goes to the valve body
To get D to engage you need at least 100psi
For R you need 150psi, this is why Reverse often slow to engage or fails first when transmission has a pressure issue

1st will often engage if one-way clutch has failed or pressure is low but D won't

In the old days ball and spring valves were used for auto shifting, and vacuum
Now-a-days a computer is used and then solenoids are used to open and close the valves

The valves engage and disengage clutches and brakes(bands)

If you remove the power(12v) from the solenoids, i.e. unplug 16 pin connector, all the solenoids close, are deactivated
If one was Leaking pressure then enough pressure might return to get D and R working again, but it wouldn't shift(2nd, 3rd, 4th) of course

If this transmission has over 200k miles I would just rebuild it, 250-300k is expected life, unless it has been rebuilt before by a marginal trans shop, then they last 18 months or 20k miles maybe

You can put in a new valve body and see how that works, this can be done without removing the transmission and not a waste of money since new valve body would be needed for a rebuild

If you look for replacement
1997 to 2011 4.0l trans will work as is if 4x4, if 2WD then you will need to swap tail shaft housing, just a few bolts, to get speedometer hook up needed in a 1997, that was removed in 1998 and up transmissions

If rebuilding ALWAYS replace
pump
one-way clutches(sprags)
OD drum
Most places don't do this and trans will fail in 18months usually

Problem now is that when i start it and put it in reverse it goes just fine but after i drive it for a bit and then go into reverse it wont move, but if i turn key off and restart truck then it will go right into reverse