This is the diagnostic procedure I will use to locate and improve the bump felt while braking to a stop in 2007 or 2008 Ford Expedition transmissions. This is exactly how I would approach it. It is easy to see how complicated and highly technological a diagnostic procedure can be. Not to mention the need for a professional scanner/diagnostic tool that costs at least $4000.00 and takes years to become proficient at using.
Never underestimate the intelligence of a top notch technician. Most competent auto technicians spend a small fortune to learn how to use their diagnostic tools, add that to practical experience and not many people can do this type of diagnostics. Check it out, here is how I would approach it.
1. Hookup Diagnostic System/Portable Diagnostic Tool with proper-Software (IDS/PDS) or equivalent and ID the vehicle.
2. Update or recalibrate the Power Control Module/Transmission Control Module (PCM/TCM) calibration using IDS release 57.8 and higher or 58.1 and higher. This new calibration is not included in the VCM 2008.9 DVD. Calibration files may also be obtained. Since the TCM cannot be independently reprogrammed, reprogram the PCM to ensure that engine and transmission calibrations are updated to the latest level simultaneously.
a. Verify that the TCM is part number 8L1P-7J104-AC (8L1P-7J104-BC for 2008 vehicles built after 12/3/2007) part number after reprogramming is complete.
b. Select the following from IDS, Tool Box, Powertrain, OBD Test Modes, Mode Level 9 Vehicle info, TCM Cal Part Number on your scan tool.
3. Clear TCM keep alive memory (KAM) and adaptive tables.
a. Using IDS:
(1) Open Toolbox.
(2) Choose Powertrain.
(3) Choose Reset KAM.
(4) Then Choose TCM.
b. Using PDS:
(1) Choose all Tests and Calibrations.
(2) Scroll down the menu and choose reset TCM KAM.
NOTE FOR PDS, RESET TCM KAM IS NOT THE SAME AS CLEAR TRANSMISSION ADAPTIVE TABLES, WHICH IS UNDER THE POWERTRAIN – TRANSMISSION MENU TREE.
NOTE UNHOOKING THE BATTERY WILL NOT CLEAR THE TCM KAM.
NOTE DO NOT CLEAR THE PCM KAM.
4. Verify that the transmission fluid temperature (TFT) PID is above 175 °F (80 °C). If it is not at 175 °F (80 °C), drive unit approximately 3 miles (5 Km) to reach temperature.
NOTE TFT MUST BE AT 175 °F (80 °C) OR ABOVE BEFORE PROCEEDING TO STEP 5.
5. Drive unit to perform adaptive shift strategy learn:
a. Accelerate from rest with light throttle to 15 MPH (24 Km/h), remove foot from accelerator pedal.
b. Brake very gently to a complete stop (allow at least six (6) seconds).
c. Repeat Steps (a-b) a total of five (5) times in the dealership parking lot or similar setting.
d. Accelerate from rest with light throttle ensuring that the 1-2, 2-3 and 3-4 shifts occur at engine speeds between 1300-1800 RPM.
e. Continue to accelerate until you achieve 50 MPH (80 Km/h) or the 5-6 upshift.
f. Brake gently to a complete stop and hold foot on brake for at least 10 seconds.
g. Repeat steps (e-f) three (3) times.
NOTE THE HARSH BUMP FELT WHILE BRAKING TO A STOP WILL BE IMPROVED. HOWEVER, SEVERAL DAYS OF DRIVING ARE REQUIRED FOR THE TRANSMISSION TO FULLY ADAPT.
I hope you get the idea. Leave your transmission diagnosis to the professionals. If you need a transmission, leave it to the most professional transmission supply company in the continental US. GotTransmissions.com can meet any replacement request for any car you have in used transmissions and any type of replacement unit. Call 866-320-1182 for a free quote.
