There is a TSB out about that problem but it was sent out for 2000-2001 LS's. However, I don't know if it is applicable to the 2003 and up LS's. Here is the TSB:
A/T - 5R55N Delayed DRIVE/REVERSE Engagements
Article No.
01-14-5
07/23/01
TRANSMISSION - 5R55N - DELAYED REVERSE OR
DRIVE ENGAGEMENTS - HARSH UPSHIFTS OR
DOWNSHIFTS - ERRATIC UPSHIFTS - DELAYED
DOWNSHIFTS NEAR 20 MPH - VEHICLES BUILT
BEFORE 10/17/2000
LINCOLN:
2000-2001 LS
This article is being republished in its entirety to include additional calibrations and to update the build date range.
ISSUE
Some vehicles built prior to 10/17/2000 with the 5R55N transmission may exhibit delayed Reverse or Drive engagements, harsh upshifts or downshifts, erratic upshifts, or delayed downshifts near 32 km/h (20 mph). This may be caused by the calibration of the Powertrain Control Module (PCM).
ACTION
Follow normal diagnostic procedures and verify the condition. If the condition is valid, reprogram the PCM to latest calibration level. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
If the vehicle is built prior to 10/17/2000 and has the conditions listed and does not have the latest PCM calibration, (see chart) reprogram the PCM. Vehicles built after 10/17/2000 are not affected by this TSB.
1. If the condition is valid, first repair all Diagnostic Trouble Codes (DTCs) that may be present.
2. Determine if the condition is caused by an internal transmission component and repair as required.
3. Clear all DTCs and validate the repair.
4. If the condition is still present or returns after repair, the PCM must be reprogrammed. Refer to the PCM Calibration Information Chart as shown.
5. Follow the procedures found in the Powertrain Control/Emissions Diagnosis (PC/ED) Service Manual and reprogram the PCM to latest calibration level.
6. After reprogramming has been completed, the transmission adaptive strategy for pressure control on engagements must be updated.
7. Install diagnostic equipment and monitor the Transmission Fluid Temperature (TFT).
8. Warm the transmission fluid to at least 54°C (130°F) as indicated by the TFT.
9. Perform five (5) engagements from Park to Reverse. Each engagement must be 5 seconds apart.
10. Perform five (5) engagements from Drive to Reverse. Each engagement must be 5 seconds apart
11. Perform five (5) engagements from Reverse to Drive. Each engagement must be 5 seconds apart.
12. Perform five (5) engagements from Neutral to Drive. Each engagement must be 5 seconds apart.
NOTE ALL OF THESE ENGAGEMENTS MUST BE PERFORMED IN ORDER FOR THE ENGAGEMENT PRESSURES TO PROPERLY ADAPT WITH THE NEW CALIBRATION.
Obtain an Authorized Modifications Decal (FPS 8262 - obtainable through DOES II, 25/pkg) and list the date, dealer number, and summary of modifications performed. Select a prominent place adjacent to the Vehicle Emission Control Information Decal suitable for installing the Authorized Modifications Decal. Clean the area, install the decal, and cover it with a clear plastic decal shield.
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 01-1-5
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage And Emissions Warranty Coverage.
OPERATION DESCRIPTION TIME
011405A Reprogram Powertrain 1.0 Hrs.
Control Module Then
Update Transmission
Adaptive Strategy (Includes
Time For Final Test Drive)
DEALER CODING CONDITION
BASIC PART NO. CODE
RECALEM 42
OASIS CODES: 501000, 502000, 503000, 504000
