A/T - Torque Converter Shudder On Light Acceleration
T-SB-0084-12
June 6, 2012
Torque Converter Shudder
Service
Category Drivetrain
Section
Automatic Transmission/Transaxle
Market
USA
Applicability
Introduction
Some 2011 - 2012 Avalon vehicles may exhibit an intermittent shudder when lightly accelerating after an upshift around the following speeds: 26mph(42km/h)(4th), 36mph(58km/h)(5th) and/or 44 mph (71 km/h) (6th). Refer to the repair procedure below for diagnostic instructions to determine if the shudder concern is related to flex lock-up and how to address this condition.
Parts Information
Warranty Information
Required Tools & Equipment
Repair Procedure Overview
1. Verify the condition.
2. Confirm the condition is related to flex lock-up operation.
3. Perform three ATF drain, refill, and test drive operations to remove contaminated fluid and resolve the concern.
^ If the condition is resolved, no further action needed.
^ If the condition is still present, replace the torque converter assembly.
Repair Procedure
1. Connect Techstream to the vehicle and perform Health Check. Confirm NO DTC(s) are stored in the ECT or ECM (SAE term: Powertrain Control Module/PCM).
Are there any DTC(s) present in the ECT or ECM (PCM)?
^ YES - This bulletin does NOT apply. Refer to the Technical Information System (TIS) and diagnose DTC(s).
^ NO - Go to step 2.
2. Test drive the vehicle and confirm condition.
3. Use Techstream to take a snapshot when shudder is occurring to determine if it's occurring during flex lockup.
Configure snapshot as follows:
All Data
30 Second Duration
Trigger Point at Midpoint (50%)
NOTE
Refer to the University of Toyota online training class P901C - "Techstream InDepth" for information about taking snapshots and graphing snapshots on Techstream.
4. Use Data List and the graphing functions of the Snapshot feature to confirm the following data parameters when the shudder condition occurs:
^ Vehicle Speed
^ Shift Status
^ Lock Up
^ SLU Solenoid Status
^ Throttle Sensor Volt%
^ If the shudder occurs with the following parameters:
^ Lock Up "OFF"
^ SLU Solenoid Status "ON"
Then the shudder is related to torque converter flex lockup. Go to step 5.
^ If the shudder occurs with the following parameters:
^ Lock Up "OFF"
^ SLU Solenoid Status "OFF"
Then the condition is NOT related to torque converter flex lockup and this bulletin DOES NOT APPLY.
Continue diagnosis to identify the root cause for this shudder.
5. Replace the automatic transaxle fluid to remove possible contamination.
A. Lift the vehicle.
NOTICE
Set the vehicle on a lift so that the vehicle is kept level when it is lifted up (make sure that the tilt angle from the front to rear of the vehicle is within +/- 1.).
B. Remove the front wheel opening extension pad LH, engine under cover LH and front fender apron seal LH.
C. Remove the refill plug and gasket from the automatic transaxle.
D. Using a 6 mm hexagon socket wrench, remove the overflow plug and gasket from the automatic transaxle.
CAUTION
Automatic transaxle fluid may be hot if the vehicle was not allowed to cool prior to draining the fluid.
E. Using a 6mm hexagon socket wrench, remove the No. 1 transmission oil filler tube from the oil pan and drain the automatic transaxle fluid.
F. Measure the amount of fluid that you drained.
HINT
Add the same amount of fluid in step I.
G. Using a 6 mm hexagon socket wrench, install the No. 1 transmission oil filler tube to the oil pan.
Torque: 1.7 N*m (17 kgf*cm, 15 in*lbf)
H. Temporarily install the gasket and the overflow plug.
HINT
Reuse the old gasket. The plug will be removed again to adjust the fluid level.
I. Add fluid to the refill hole using the same amount of fluid drained in step F.
NOTICE
Use Toyota Genuine ATF WS.
J. Temporarily install the gasket and refill plug to avoid fluid spillage.
HINT
Reuse the old gasket. The plug will be removed again to adjust the fluid level.
K. Lower the vehicle.
L. Start the engine.
M. Slowly move the shift lever from P to D, and then back to P.
N. Allow the engine to idle for 30 seconds to warm it up.
O. Turn the engines witch off.
P. Adjust fluid temperature, then adjust fluid level.
Refer to the Technical Information System (TIS), applicable model and model year Repair Manual:
^ 2011/2012Avalon:
Drivetrain - Automatic Transmission/Transaxle - "U660E Automatic Transaxle: Automatic Transaxle Fluid: Adjustment"
6. Test drive the vehicle until the A/T oil temperature has reached and maintained 160°F (71°C) for at least 10 minutes.
7. Repeat steps5and6two more times.
HINT
Only replace the refill and overflow plug gaskets with new ones on the 3rd fluid adjustment procedure.
8. Perform a leak check and reassembly.
A. Lift the vehicle.
B. Clean each part.
C. Check for fluid leaks.
D. Install the front wheel opening extension pad LH, engine under covers LH and front fender apron seal LH.
E. Lower the vehicle.
9. Is the shudder concern resolved?
^ YES - The repair is completed.
^ NO - Go to step 10.
10. Replace the torque converter.
Refer to TIS, applicable model and model year Repair Manual:
^ 2011 Avalon:
Drivetrain - Automatic Transmission/Transaxle "U660E Automatic Transaxle: Automatic Transaxle Assembly: Removal (to 12/2010) / Removal (from 12/2010) / Installation (to 12/2010) / Installation (from 12/2010)"
^ 2012Avalon:
Drivetrain - Automatic Transmission/Transaxle - "U660E Automatic Transaxle: Automatic Transaxle Assembly: Removal / Installation"
11. Adjust the transmission fluid level in the transmission.
NOTICE
Failure to use WS transmission fluid and to properly adjust transmission fluid level can cause transmission shifting issues, MIL "ON", and/or transmission damage.
Refer to TIS, applicable model and model year Repair Manual:
^ 2011/2012 Avalon:
Drivetrain - Automatic Transmission/Transaxle - "U660E Automatic Transaxle: Automatic Transaxle Fluid: Adjustment"
12. Test drive the vehicle and confirm the shudder condition is eliminated.
© 2012 Toyota Motor Sales, USA