Propeller Shaft - Shudder During Launch

87chrysler20

Models

1987-88 124" W.B. "N" Truck 2 W.D. With 998 Automatic Transmission

Subject

Propeller Shaft Shudder During Launch From 0-10 MPH and/or Vibration & Booming Noise at 35-50 MPH

Index

PROP SHAFT & U-JOINTS

Date

December 31, 1987

No.

16-02-87 (C2-16)
SYMPTOM/CONDITION

1. Vehicle shudders during launch from 0 - 10 MPH. The condition becomes more apparent as vehicle is loaded.

2. Vehicle exhibits vibration and noise in the 35-50 mph range.

DIAGNOSIS

Attach a tachometer to read engine RPM.

Road test the vehicle to verify the condition.

The diagnosing procedure for launch shudder is performed from a standing start. Accelerate with medium-heavy acceleration from 0-15 mph while watching for shudder. If shudder is evident, note the engine RPM.

In the case of vibration and/or booming noise, road test the vehicle in the 35-55 mph range. If a vibration and/or booming noise is evident, note the engine RPM where the problem is most perceptible.

With the vehicle stopped, and transmission in neutral, run the engine up through the same RPM ranges and note if the same phenomenon is present.

If neither of these problems are present while running up the engine, and either or both of the above conditions have been verified, it will be necessary to remove the 2-piece propeller shaft and install a single-piece shaft as follows:
PARTS REQUIRED

1 Shaft (124" W.B. W/7-1/4 Rear Axle) PN 4384625
1 Shaft (124" W.B. W/8-1/4 Rear Axle) PN 4384605

REPAIR PROCEDURE

This repair involves removal of 2-piece propeller shaft and replacing it with a 1-piece propeller shaft.

1. Remove front and rear propeller shaft assembly.

2. 1988 models: Unbolt and remove propeller shaft center bearing support cross member.

1987 models: Remove the propeller shaft center bearing support cross member by using an air chisel to remove the crossmember-to-frame rivets. Discard the crossmember.

3. Install new one-piece propeller shaft and torque U-joint strap bolts to 68 N-m (14 foot pounds).

4. Road test the vehicle to verify repairs.

POLICY: Reimbursement within the provision of the warranty

REAR WHEEL DRIVE LABOR OPERATION TIME SCHEDULE:

TIME ALLOWANCE:
Labor Operation No. 16-30-01-95 - 1987 . . . . . . . . . . 1.1 Hrs.
1988 . . . . . . . . . . 0.7 Hrs.

FAILURE CODE: 2X - Vibration or Chatter