Tranny Question

[brlarl]

I just recently noticed what appears to be a "pulling or dragging" feeling coming from my transmission shifting into 2nd gear. After it shifts to 2nd it runs fine. I does not do it all the time but if I run into the corner store and leave it idling with the wife and kids in it then go to leave it will do it(sometimes). It will also do it sometimes at a light or stop sign. The odometer reads at right under 130,000 miles, fluid is full and it is not red nor brown (burnt) in color and does not smell burnt. I have had it since new and unfortunately never changed out the fluid or filter. I know changing all the fluid now will almost guarantee tranny failure but what if I just change the filter and whatever fluid that is in the pan? Will that hurt anything? Any suggestions? Thanks

[VileZambonie]

What color is the fluid if it's not red and it's not brown? You'll have to elbaorate on what it's doing better.

[brlarl]

It is a faint red color (pinkish), occasionally when it shifts into first gear it revs up like it should between shifts and then right before it goes into second it feels as if it is pulling then it goes completely into second then all shifts after that are smooth.  The truck is a daily driver to and from work then it is taken on the occasional trip with about 1,000 miles round trip every 3 years or so.  There is also absolutely no towing with the truck just daily normal driving (by my wife which she has a light foot), if more info is needed please let me know.............Thx.

[VileZambonie]

What do you mean pulling?  It should pull you ahead.... pink is good... do you mean it shifts soft?

[brlarl]

No, I revs up as normal between shifts but then it shifts into second a little bit sooner then we expect it to making it feel as if something it dragging behind the truck not wanting to let it continue its forward momentum but once it shifts through the other gears all is well.  It seems like the RMPs drop too much when it shifts into 2nd opposed to being a smooth transition.  I would compare it to driving a stick shift and going from second down to first gear, you know how it boggs down or drags?  Again it does it every now and then and not hard.  If pink is good, do you think it will hurt anything if I change just the fluid in the pan and the filter or will I be safe to change all the fluid?  Remember I never changed for added to the fluid and its just under 130,000 miles on it.  Thanks

[VileZambonie]

Go ahead and change the fluid and filter. Tighten the tv cable up 2 clicks and see how it shifts. This is a 700R4 right?

[brlarl]

Actually no it's on a non-chevy vehicle but I figured the fluid condition should basically be the same for all makes.  Meaning the condition of the fluid should tell it all. Sorry to throw this in there like that but you guys (mainly you) sound like to know quite a bit about automotives in general.  Please email me to the side if you wish to continue assisting with this question.  Thank You

[VileZambonie]

I will move this thread to General Discussion and please provide the vehicle information.

[brlarl]

Thanks, the vehicle is actually a 2001 F +++ Expedition with 4.6L.  Again its been owned since new but the fluid in the tranny has never been changed.  Over all the tranny runs good except for that small issue.  Let me know if you need more info.  Thanks again.

[zieg85]

I can't speak for your transmission but... A close friend of the family had a Lincoln that did the same very thing you are describing, actually she said that was her indication to have the fluid/filter changed.  Always made it shift like new after she had it done.  Hope you luck out...

[VileZambonie]

If it has an inline filter change that also. I use a new flush system that actually works unlike the earlier machines. It exchanges 16 quarts after we run a cleaning solution through the trans. After the flush is complete we add a conditioner and it does often help quirks but it's a PM not a repair.Try servicing it first and see what happens.

[brlarl]

Thanks Guys, I'll give it a try this weekend.

[brlarl]

Can you tell me if there F+++s have any type of adjustments the the TV cable on the 700R4.  I honestly don't know too much about these Fix Or Repair Daily vehicles , lol.   Actually the only reason we have it is because that is what mama wanted and that is what she got.  I tried to get a Tahoe at the time but I have to agree with her when she said it was roomier then the Tahoe.

[VileZambonie]

It's electronic controls. You may want to check with your dealer and find out if there are any flash updates available which there proabaly is.

Transmission Electronic Control System

Electronic System Description
The Powertrain Control Module (PCM) and its input/output network control the following transmission operations:


shift timing
line pressure (shift feel)
torque converter clutch
The transmission control is separate from the engine control strategy in the PCM, although some of the input signals are shared. When determining the best operating strategy for transmission operation, the PCM uses input information from certain engine-related and driver-demand related sensors and switches.
In addition, the PCM receives input signals from certain transmission-related sensors and switches. The PCM also uses these signals when determining transmission operating strategy.
Using all of these input signals, the PCM can determine when the time and conditions are right for a shift, or when to apply or release the torque converter clutch. It will also determine the best line pressure needed to optimize shift feel. To accomplish this the PCM uses hydraulic solenoids to control transmission operation.
The following provides a brief description of each of the sensors and actuators used to control transmission operation.

Mass Air Flow (MAF) Sensor
The Mass Air Flow Sensor (MAF) measures the mass of air flowing into the engine. The MAF sensor output signal is used by the Powertrain Control Module (PCM) to calculate injector pulse width. For transmission strategies the MAF sensor is used to regulate electronic pressure control EPC, shift and torque converter clutch scheduling.

Powertrain Control Module (PCM)
The operation of the transmission is controlled by the Powertrain Control Module (PCM) . Many input sensors provide information to the PCM. The PCM then controls actuators which determine transmission operation.

Transmission Control Switch (TCS) and
Transmission Control Indicator Lamp (TCIL)
The Transmission Control Switch (TCS) is a momentary contact switch. When the switch is pressed, a signal is sent to the PCM to allow automatic shifts from first through fourth gears or first through third gears only.
The PCM energizes the Transmission Control Indicator Lamp (TCIL) when the switch is off. The TCIL indicates overdrive cancel mode activated (lamp on) and Electronic Pressure Control (EPC) circuit shorted (lamp flashing) or a monitored sensor failure.

Output Shaft Speed (OSS) Sensor
The Output Shaft Speed (OSS) sensor is a magnetic pickup, located at the output shaft ring gear, that sends a signal to the powertrain control module to indicate transmission output shaft speed. The OSS is used for torque converter clutch control, shift scheduling and to determine electronic pressure control.

Digital Transmission Range (TR) Sensor
The digital Transmission Range (TR) sensor is located on the outside of the transmission at the manual lever.
The digital TR sensor completes the start circuit in Park and Neutral, the back-up lamp circuit in Reverse and the neutral sense circuit (4x4 only) in Neutral. The digital TR sensor also opens and closes a set of four switches that are monitored by the Powertrain Control Module (PCM) to determine the position of the manual lever (P. R. N. D, 2, 1).

Transmission Fluid Temperature (TFT) Sensor
The Transmission Fluid Temperature (TFT) sensor is located on the lead frame assembly near the shift solenoids on the main control valve body. It is a temperature sensitive device called a thermistor. It sends a voltage signal to the PCM. The voltage signal varies with transmission fluid temperature. The PCM uses this signal to determine whether a cold start shift schedule is necessary. The shift schedule is compensated when the transmission fluid temperature is cold. The PCM also inhibits (TCC) operation at low transmission fluid temperatures and corrects electronic pressure control.

Vehicle Speed Sensor (VSS)
The Vehicle Speed Sensor (VSS) is model dependent.
Possible sources of vehicle speed input are, Anti-Lock Brake Sensor (ABS) , a gear-driven Vehicle Speed Sensor (VSS) , or the transmission Output Shaft Speed (OSS) sensor. On 4x4 applications with a manual shift transfer case, the transfer case speed sensor is the source of vehicle speed. The VSS signal is either an AC signal whose frequency changes with vehicle speed, or an SCP data message depending on the source. Some vehicles have both. The vehicle speed signal is an input to various vehicle sub-systems such as the Powertrain Control Module (PCM) , instrument cluster (speedometer and odometer), speed control systems, etc. The vehicle speed source must be Operational to enter output state control mode for diagnostics.

Electronic Pressure Control (EPC) Solenoid
The Electronic Pressure Control (EPC) solenoid regulates transmission pressure. EPC valve pressure is used to control line pressure.

Shift Solenoid-SSA, SSB
Two on/off shift solenoids provide gear selection of first through fourth gears by controlling the pressure to the three shift valves. One unit containing the two shift solenoids is located in the main control valve body.
The shift solenoids are two-way normally open style.

Solenoid Operation Chart

 
 
 
 


a - When a manual pull-in occurs above a calibrated speed the transmission will downshift from the higher gear until the vehicle speed drops below this calibrated speed.

EC = Electronically Controlled.
HD = Hydraulically Disabled.

Torque Converter Clutch (TCC) Solenoid
The Torque Converter Clutch (TCC) solenoid is used to control the apply and release of the TCC.

4x4 Low (4x4L) Switch
The 4x4 low (4x4L) range switch is located on the transfer case cover. It provides an indication of when the 4x4 transfer case gear system is in the low range.
The PCM then modifies shift schedule for 4x4L operation.

Brake Pedal Position (BPP) Switch
The Brake Pedal Position (BPP) switch tells the Powertrain Control Module (PCM) when the brakes are applied. The torque converter clutch disengages when the brakes are applied. The BPP switch closes when the bakes are applied and opens when they are released.

Electronic Ignition (EI) System
The electronic ignition consists of a crankshaft position sensor, two four tower ignition coils and the Powertrain Control Module (PCM) . The ignition control module operates by sending crankshaft position information from the crankshaft position sensor to the ignition control module. The ignition control module generates a Profile Ignition Pickup (PIP) signal (engine rpm) and sends it to the PCM. The PCM uses PIP signal in the transmission strategy, Wide-Open Throttle (WOT) shift control, torque converter clutch control and EPC pressure.

Air Conditioning (A/C) Clutch
An electromagnetic clutch is energized when the clutch cycling pressure switch closes. The switch is located on the suction accumulator/drier. The closing of the switch completes the circuit to the clutch and draws it into engagement with the compressor driveshaft.
When the A/C clutch is engaged, Electronic Pressure Control (EPC) is adjusted by the PCM to compensate for additional load on the engine.

Intake Air Temperature (IAT) Sensor
The Intake Air Temperature (IAT) sensor provides the Sequential Fuel Injection (SFI) system mixture temperature information. The IAT sensor is used both as a density corrector for air flow calculation and to proportion cold enrichment fuel flow. The IAT sensor is installed in the air cleaner outlet tube. The IAT sensor is also used in determining Electronic Pressure Control (EPC) pressures.

Engine Coolant Temperature (ECT) Sensor
The Engine Coolant Temperature (ECT) sensor detects temperature of engine coolant and supplies the information to the Powertrain Control Module (PCM) .
The ECT sensor is used to control Torque Converter Clutch (TCC) operation. The ECT is installed in the heater outlet fitting or cooling passage on the engine.
For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and air-to-fuel ratio as a function of engine coolant temperature.

Throttle Position (TP) Sensor
The Throttle Position (TP) sensor is a potentiometer mounted on the throttle body. The TP sensor detects the position of the throttle plate and sends this information to the Powertrain Control Module (PCM) .
The TP sensor is used for shift scheduling, electronic pressure control and Torque Converter Clutch (TCC) control.

 
 

[brlarl]

Thanks, Vile.