A/T - Poor Shift Quality
No: LM-307-001Issue: 1
Date: 27 Sep 2005
SECTION: 307-01
Poor Shift Quality
AFFECTED VEHICLE RANGE:
Range Rover (LM)
6A164412 - 6A203248 (Naturally Aspirated vehicles ONLY)
CONDITION SUMMARY:
ADAPTIONS INCOMPLETE OR FLUID CONTAMINATION
At the Vehicle Preparation stage or very early customer use, poor shift quality may be experienced by the technician or the customer.
Cause: It is possible that the vehicle has not accumulated sufficient mileage for transmission adaptions to be made or that the presence of the transit relay has prevented proper adaptions. An alternate cause for poor shift quality could be water-contaminated AT fluid.
Action: Should a customer express concern regarding the above, refer to the Repair Procedure detailed in this bulletin for inspection and repair processes.
PARTS:
WARRANTY:
NOTE:
Repair procedures are under constant review, and therefore times are subject to change; those quoted here must be taken as guidance only. Always refer to DDW to obtain the latest repair time.
DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
Normal warranty policy and procedures apply.
REPAIR PROCEDURE
ADAPTION CYCLE FOR THE 6HP26 TRANSMISSION
NOTE:
The transmission should reach normal operating temperature 80-90 °C (176-194 0F) at least once (to expel any air in the system) before commencing the adaption cycle. For transmission adaption to take place, the transmission should be at a temperature higher than 30 °C (86 °F). The transmission temperature should be achieved by driving the vehicle at various speeds and loads in "Normal" mode.
1. Verify that the conditions in the NOTE above have been met and select "D" (drive) transmission mode to perform adaptation cycle as follows:
^ Accelerate gently to 50-55mph (80-90 kph) 50 6th gear is engaged. All upshifts should be positive throttle shifts, no overrun shifts
^ Coast down (decelerate) vehicle to a standstill without using the brakes until 2nd gear is engaged or below 10mph (16 kph).
^ Apply gentle braking to bring the vehicle to rest.
^ Hold vehicle stationary using brakes for 15 seconds.
2. Repeat step 1 a total of five times.
NOTE:
Step 3 is a test to establish if the phenomenon described as "tip-in-thump" (harsh 2-1 downshift or 1-2 up-shift) remains evident.
3. Perform final adaptation cycle steps as follows:
^ Accelerate gently to 15mph (25kph).
^ Apply brake firmly and rapidly decelerate to 1mph (2kph).
^ Rapidly apply 50% to 75% throttle.
4. Repeat step 3 for a total of six times.
5. If no "tip-in-thump" is experienced during this adaption cycle the vehicle is suitable for customer hand-over and no further work is required.
6. If a hard 2-1 downshift is observed during the adaption process, perform the following oil sample check:
^ Raise vehicle on a suitable vehicle lift.
^ Position a clean drain container under the transmission.
NOTE:
A transmission fluid sample of approximately 100ml (3.5 oz) is all that is required.
^ Loosen and remove the transmission filler plug and collect a 100ml transmission fluid sample.
^ Clean, install and tighten the transmission filler plug to 35Nm (261b-ft).
^ Transfer the transmission fluid from the drain container to a suitable clear container to allow inspection.
NOTE:
GTR lookup sequence is as follows:
GTR Home > NAS > Service Information/ LM-Range
Rover/2006 > Workshop Manuals > Range Rover 2006
Workshop Manual > Bookmark "307-01B Automatic
Transmission/Transaxle 4.4L" > Link "Removal and
Installation - Transmission"
7. Compare the oil sample to the illustration. (Figure 1)
a) If the transmission oil sample taken resembles sample
"B" in the illustration with a milky discoloration, refer to
GTR Section 307-01 and replace the following components:
^ Transmission assembly
^ Transmission cooler lines
^ Transmission cooler.
b) If the oil sample resembles sample "A" in the illustration, perform "Transmission Flush Procedure" as outlined in the following section.
NOTE:
If the transmission and related components has been replaced with a new unit because of visible contamination (sample "B" in Figure 1), there is no requirement to perform any flush procedure.
The flushing procedure below is only intended for vehicles that exhibit a "tip-in-thump" symptom, but have a transmission fluid sample as shown in Figure 1 sample "A".
TRANSMISSION FLUSH PROCEDURE
1. Loosen and remove the transmission drain plug and allow fluid to drain into a clean container.
2. Remove the transmission sump pan and drain transmission fluid into the same container used to collect drain plug fluid.
3. Inspect for traces of water and clean the sump pan.
4. Install the transmission sump pan.
5. Clean, install and tighten original transmission drain plug to 9Nm (71b-ft).
6. Transfer transmission fluid from the drain container to a suitable measuring beaker and measure the quantity collected.
7. Record the collected quantity of transmission fluid for future reference and discard the drained fluid.
8. Clean the measuring jug.
9. Perform the following steps to flush the transmission thoroughly:
a) Measure new transmission fluid equal to the quantity recorded above in step 7.
b) Loosen and remove the transmission filler plug.
c) Using a clean syringe, fill the transmission with some of the measured fluid to the filler plug level.
d) Turn ignition "ON".
e) Ensure the transmission selector lever is in "P" (Park) and the handbrake is applied.
f) Start the engine.
g) Immediately fill the transmission with remainder of the measured new transmission fluid.
h) Install and tighten transmission filler plug to 35 Nm (26lb-ft).
i) Apply footbrake.
j) Shift through transmission selector lever positions from "P" to "R", "N" and "D" and back to "N".
k) With the selector lever in "N" (Neutral), raise engine speed to 1500rpm for one to two minutes.
l) Return selector lever to "P".
m) Release footbrake.
n) Switch off engine.
o) With the drain container under the transmission, loosen and remove the transmission drain plug.
p) Allow transmission fluid to drain completely.
q) Clean and install original drain plug on the first three cycles. On the fourth cycle install a new drain plug.
10. Perform step 9 until the transmission has been flushed and drained a total of four times.
11. Measure new transmission fluid to the recorded drained fluid amount plus 0.5 liter (17 oz) into the clean measuring jug.
12. Loosen and remove transmission filler plug.
13. Using a clean syringe, fill the transmission with some of the measured fluid to the filler plug level.
NOTE:
T4/WDS must be loaded with software release LR CD08 or later.
14. Connect T4 WDS to the vehicle and initiate a diagnostic session.
15. Enter vehicle VIN and navigate to Content Model screen.
16. Select "Transmission System".
17. Press the "Datalogger" icon tab at the top of the screen.
WARNING:
To avoid unanticipated vehicle movement, during the following portion of the test the vehicle must have the hand brake set and the transmission must be in the Park "P" position.
18. Verify that the handbrake is set, and the transmission is in the Park "P" position.
19. Select and view "Transmission Oil Temperature" signal in WDS.
20. Start the engine when instructed.
21. Select the "continue" button to monitor temperature.
22. Immediately fill the transmission with remainder of measured fluid to filler hole level (fluid running from hole).
23. Install and tighten transmission filler plug to 35 Nm (26lb-ft).
24. Perform the following brake fluid level check:
a) Apply footbrake.
b) Shift through transmission selector lever positions from "P" to "R", "N" and "D" and back to "N".
c) With the selector lever in "N" (Neutral), raise engine speed to 1500rpm for one to two minutes.
d) Return selector lever to "P".
e) Release footbrake.
f) Allow transmission fluid temperature to reach 37°C (98° F).
g) Loosen and remove and discard the transmission filler plug.
NOTE:
GTR lookup sequence is as follows:
GTR Home > NAS > Service Information/ LM-Range Rover 12006 > Workshop Manuals> Range Rover 2006 Workshop Manual > Bookmark "204-06 Ride and Handing Optimization" > Link Transmission Fluid Level Check (44.24.06)
h) Refer to GTR section 307-01 and allow the transmission fluid to drain from the filler plug hole until it becomes a slow trickle.
CAUTION:
The transmission fluid temperature must not exceed 50°C (122 °F) during the level check.
25. If the transmission fluid has exceeded 50°C (122 °F), install the transmission filler plug, allow the transmission to cool and repeat the complete level check in Step 24.
26. When level check is successfully completed, install the new transmission filler plug and tighten to 35Nm (26lb-ft).
27. Clean fluid residue from transmission.
28. Remove drain container.
29. Switch off the ignition.
30. End the diagnostic session, turn off 14 and disconnect from the vehicle.
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