Suspension/Drivetrain - Shudder On Hard Acceleration
TECHNICALBulletin No.: 09-03-08-009B
Date: June 07, 2010
Subject: Shudder in Vehicle Under Moderate to Hard Acceleration (Insert Washers Under RDM and/or Replace Front Springs and/or Replace Halfshaft)
Models:
2010 Chevrolet Equinox
2010 GMC Terrain
with 2.4L L4 or 3.0L V6 Engine
Built Prior to VIN Breakpoint A6247602
Please Refer to GMVIS
Supercede:
This bulletin is being revised to add vehicle information to the titles in the Correction section. Please discard Corporate Bulletin Number 09-03-08-009A (Section 03 - Suspension).
Condition
Some customers may comment on these shudder conditions:
- Lateral shudder - Occurs during accelerator apply (moderate to heavy). Can be intermittent and usually noticeable powering through turns at 40 km/h (25 mph) or less.
Diagnostic Tip
Accelerate the vehicle under moderate to hard pedal. Note that this shudder depends on relative phasing (orientation) of the front halfshaft joints to each other. So, if a shudder does not occur, this may require re-evaluation after or during a turn (such as driving one way down a street and then repeating in the other direction). It is usually noticeable with moderate accelerator apply during a turn at lower speeds.
- Vertical shudder - Occurs during moderate to heavy accelerator apply (32-40 km/h (20-25 mph) and is not intermittent.
Diagnostic Tip
Drive the vehicle in a straight line under moderate to hard acceleration (going up a grade will worsen it).
- Lateral wobble (low frequency / high amplitude shudder) (Only on V6 AWD and FWD) - Occurs during acceleration (light, moderate, or heavy). Most noticeable around 64 km/h (40 mph) and up and can be very intermittent (comes and goes at random). Sometimes appears briefly and other times will stay for an extended period of time.
Diagnostic Tip
Requires accelerator apply and can be very intermittent. If left front halfshaft - will be worse when turning to left (lifting left side of vehicle); If right front halfshaft - will be worse when turning to right (lifting right side of vehicle).
Cause
This condition may be caused by the standing height of the AWD configurations, which may be too high, increasing the axle joint angles beyond their optimum operating range. The shudder may vary based on the relative phasing of the left and right halfshaft joints.
Correction
Important
Do Not replace the front drive axles.
Important
Do Not replace springs for FWD configuration.
Verify the condition. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in SI. Inspect the vehicle to see if the RDM bushings have the washers installed between the top of the bushing and the cradle (1). If not, see the procedure for Installing RDM Washers first. If the condition still occurs, then proceed to Replacement of Front Springs. If adding RDM washers and replacing the spring still do not fix this condition, replace the halfshafts.
Installing RDM Washers - Only for All-Wheel Drive (AWD)
1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in SI.
2. Remove the exhaust system from the four rubber hangers.
3. Support the rear differential with a transmission jack stand.
4. Remove the rear differential support bushing bolts (1).
5. Remove the front mounting nuts for the rear differential.
6. Lower the rear differential to gain access and insert washers, GM P/N 11609719, between the top of the bushing and the cradle.
7. Raise the rear differential assembly into place.
8. Tighten the front mounting nuts.
Tighten
Tighten the nuts to 122 Nm (90 lb ft).
9. Tighten the rear differential support bushing bolts.
Tighten
Tighten the bolts to 188 Nm (139 lb ft).
10. Remove the transmission jack stand.
11. Install the exhaust system in the hangers.
12. Lower the vehicle.
13. Verify that the condition is corrected. If not, proceed to Replacement of Front Springs.
Replacement of Front Springs - For Both 4 and 6 cylinders; All-Wheel Drive (AWD) Only
1. Verify the shudder in the vehicle under hard acceleration.
2. Replace the front springs with GM P/N 20827083 (2.4L L4 Engine) or 20827104 (3.0L V6 Engine). Remove the front struts from the vehicle. Refer to Strut Assembly Replacement in SI.
3. After the struts are removed from the vehicle, replace the springs. Refer to Strut, Strut Component, and Spring Replacement in SI.
Replacement of Halfshaft - Only for V6; FWD and All-Wheel Drive (AWD)
1. Verify the Lateral wobble/shudder in the vehicle under light/hard acceleration.
2. Replace the front wheel drive shaft. Refer to Front Wheel Drive Shaft Replacement in SI. Refer to the GM electronic parts catalog (EPC) for the correct front wheel drive shaft.
Parts Information
Warranty Information
For vehicles repaired under warranty, use the table.
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