Tech Tip: Acura with Idle Vibration/Harsh Shifting Issue – UnderhoodService

Tech Tip: Acura with Idle Vibration/Harsh Shifting Issue

If a customer complains of a vibration at idle or harsh engagement when shifting the transmission between Park, Drive and Reverse, the probable cause is the front hydraulic engine mount may have deteriorated and torn.

Applies To: all 2001-’03 3.2 CL and MDX, 2004 MDX VIN 2HNYD1…4H500001 thru 2HNYD1…4H557556 and all 2000-’03 3.2 TL

If a customer complains of a vibration at idle or harsh engagement when shifting the transmission between Park, Drive and Reverse, the probable cause is the front hydraulic engine mount may have deteriorated and torn.

Diagnosis
1. Bring the engine up to operating temperature, and fully apply the parking brake. figure 1

2. For manual-transmission-equipped vehicles:
Have an assistant stand to the side of the engine compartment to watch the top of the front engine mount. With the engine running at 2,000 rpm, slowly engage the clutch. Your assistant should be looking for contact between the top of the engine mount and the bottom of the engine mount bracket, and listening for noise from that area.

For automatic-transmission-equipped vehicles:
Have an assistant stand to the side of the engine compartment within view of the top of the front engine mount. Shift the transmission to Drive. With your foot firmly on the brake pedal, quickly depress the accelerator pedal and release it. Your assistant should be looking for contact between the top of the engine mount and the bottom of the engine mount bracket, and listening for noise from that area.

3. If there is contact and/or noise, go to Repair Procedure.

Repair Procedure
1. Place the vehicle on a lift, but do not raise it.

2. Remove the top nut from the front hydraulic engine mount. See Figure 1.

3. Remove the top bolt from the front engine mount bracket.

4. Remove the four nuts and bolts that secure the front engine mount retaining bracket.

5. Remove the three accessible bolts holding the engine mount to the subframe.

6. Raise the vehicle. Place a screw jack under the transmission next to the engine and raise the
transmission slightly.

figure 2 7. Remove the two remaining front bracket bolts. See Figure 2.

8. Disconnect the engine mount vacuum line, and remove the last engine mount bolt.

9. Lower and remove the screw jack, then lower the vehicle.

10. Place a floor jack where the screw jack was, and raise the transmission until the bracket clears the engine mount stud.

11. Remove the front bracket and the engine mount.

12. Remove the four nuts and bolts holding the retaining bracket to the new engine mount, and remove the retaining bracket. See Figure 3.

13. Position the engine mount on the subframe. Install the engine mount bolts loosely.

14. Install the retaining bracket on the engine mount.

15. Install the front bracket and the passenger-side bracket bolt, threading it halfway in.

16. Torque all four engine mount bolts to 34 Nm (25 lb.-ft.).

17. Reconnect the vacuum line.Figure 3

18. Lower the transmission, and remove the floor jack. Install the four retaining bracket nuts and bolts, and torque them to 22 Nm (16 lb.-ft.).

19. Install the remaining two bolts to the front bracket, and torque them to 38 Nm (28 lb.-ft.).

20. Install and torque the top engine mount nut to 54 Nm (40 lb.-ft.).

Courtesy of Mitchell 1.

You May Also Like

Lifter Deactivation

The area of contact between the lifters and cam lobes is the highest loaded surface inside an engine.

The basic function of a valve lifter is pretty simple. It sits on the camshaft and transfers the motions of the cam lobe up through the pushrods and rockers to open and close the valves. The size and shape of the cam lobe under the lifter (multiplied by the ratio of the rocker arms) determine valve lift and duration. As such, the lifter just follows the motions of the cam. But, it does play a role in valvetrain lash (clearance) and noise.

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.

Ignition System Do’s and Don’ts

Why do ignition systems give technicians problems when diagnosing ignition-related misfires? The answer is that some technicians use tests that might give inconclusive results or do damage to the coil or drivers inside a module.

Tools To Service Serpentine Belts

Servicing the serpentine belt on some vehicles is a tough task.

Other Posts

Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

Why Do Timing Chains Stretch?

As the timing chain wears, it can change the timing of the camshaft and crankshaft.

Carbon Deposits and Direct Injection Engines

The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves.

Hyundai & Kia Hybrid Drivetrain

The Hyundai hybrid system has a motor control unit (MCU) and hybrid control unit (HCU).