Body/Driveline - Vibration/Body Boom/Shake
88ford05
VIBRATION - DRIVELINE - BODYBOOM, Article No.
HARSHNESS AND SHAKE 88-6-19
FORD: 1986-87 CROWN VICTORIA
LINCOLN-MERCURY: 1986-87 GRAND MARQUIS, LINCOLN TOWN CAR
ISSUE: Driveline vibration, body boom, harshness or shake at speeds between 35 and 65 mph (56 and 105 km/h) may be caused by one or more vehicle components. The areas that contribute to these concerns are wheel runout, driveshaft and U-joints, body-to-frame alignment, rear shock absorbers, rear axle housing or rear axle ring and pinion gears.
ACTION: To correct this, use the following diagnostic procedure to determine which areas require attention.
NOTE: The first step in correcting these concerns is performing a thorough road test.
1. A VISIBLE shake between 35 and 65 mph (56 and 105 km/h) in the steering wheel, steering column, floor pan, seats and the front sheet metal may be serviced by referring to the 1987 Car Shop Manual, Volume A, Section 18, "HIGH SPEED SHAKE DIAGNOSIS", Step A8 and the following wheel runout procedure.
a. With a roller point installed on the dial indicator, measure wheel rim radial runout.
b. If measurement exceeds .045" (1.14 mm), install a new wheel E2AZ-1007-A (15" x 6") or E6AZ-1007-A (15" x 6.5")
NOTE: Match the high point of the tire to the low point of the wheel assembly.
c. Balance the wheel and tire assembly.
d. Install the wheel on the vehicle.
2. A vibration or shudder FELT between 40 and 50 mph (64 and 80 km/h) along with a "rumbling" or "booming" NOISE may be serviced by inspecting and correcting the driveshaft U-joints for correct movement. Refer to the 1987 Car Shop Manual, Volume A, Section 18.
NOTE: A U-joint that is free in one direction but tight in the other can cause low speed vibration.
3. A vibration FELT between 50 and 65 mph (80 and 105 km/h) along with a "drone", "humming", or "booming" NOISE may be serviced by balancing the driveshaft on the vehicle. Refer to the 1987 Car Shop Manual, Volume A, Section 18, Steps F1 through F4. This will compensate for excessive companion flange runout and driveline imbalance.
4. A power deck lid closure mechanism that pulls down too much on the deck lid or a deck lid that is excessively tight will increase the vehicle sensitivity to driveline NOISE. This can be serviced by performing the adjustment procedures outlined in the 1987 Car Shop Manual, Volume A, Section 44-12.
5. On Lincoln Town Cars only, make sure the aluminum-backed self-adhesive mastic panels that are used to lessen the effects of driveline vibration are secured to the center of the rear fender quarter panels. To make sure the bond is okay, use a screwdriver handle to apply a load to the entire mastic panel.
6. Harshness FELT between 20 and 65 mph (32 and 101 km/h) when the vehicle passes over tar strips and expansion joints can be serviced by inspecting and correcting the body-to-frame alignment. Refer to TSB 85-24-15 for detailed service information.
NOTE: When inspecting the body mounts, the vehicle must be supported by the front lower control arms and the rear axle. The rear axle must be supported by a moveable two (2) post hoist or adjustable safety stands.
7. If the vibration has not been reduced to an acceptable level after performing Steps 1 through 6, inspect the shock absorbers for sticking and binding using the following procedure.
a. Remove the rear shock absorbers.
b. Collapse the shock absorbers by hand and allow them to extend by themselves from the internal pressure. If the shock absorbers do not extend freely, obtain new shock absorbers, E5AZ-18125-A.
c. Install the shock absorbers.
8. If the vibration has not been reduced to an acceptable level after performing Steps 1 through 7, perform the Bent Axle Housing Diagnostic procedure as outlined in the 1987 Car Shop Manual, Volume D, Section 15-01. If the axle housing is okay, install a new service replacement rear axle gear set. Refer to the 1987 Car Shop Manual, Volume D, Section 15-06 for detailed service information. Refer to the rear axle gear set application chart on this page for the correct service part number.
REAR AXLE GEAR SET APPLICATION CHART
Ring Gear Size Ratio Service Part
8.8" 2.73:1 E7AZ-4209-C
8.8" 3.08:1 E7AZ-4209-D
8.8" 3.27:1 E7AZ-4209-A
PART NUMBER PART NAME CLASS
E2AZ-1007-A Wheel Assembly AM
E6AZ-1007-A Wheel Assembly BM
E5AZ-18125-A Shock Absorber BM
E7AZ-4209-A Gear Set B
E7AZ-4209-C Gear Set B
E7AZ-4209-D Gear Set B
OTHER APPLICABLE ARTICLES: 85-24-15
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION: 880619A - Step 1 (Check wheel runout - All)
TIME: 0.5 Hr.
OPERATION: 880619B1 - Step 1 (Replace wheel assembly)
TIME: 0.5 Hr. - One wheel
OPERATION: 880619B2 - Step 1 (Replace wheel assembly)
TIME: 0.7 Hr. - Two wheels
OPERATION: 880619B3 - Step 1 (Replace wheel assembly)
TIME: 1.2 Hrs. - Three or four wheels
OPERATION: 880619C - Step 2
TIME: 0.4 Hr.
OPERATION: 880619D - Step 3
TIME: 2.4 Hrs.
OPERATION: 880619E - Step 4
TIME: 0.3 Hr.
OPERATION: 880619F - Step 5
TIME: 0.3 Hr.
OPERATION: 880619G - Step 6
TIME: 1.6 Hrs.
OPERATION: 880619H - Step 7
TIME: 0.8 Hr.
OPERATION: 880619J - Step 8 (Check axle housing)
TIME: 0.5 Hr.
OPERATION: 880619K - Step 8 (Replace gear set)
TIME: 2.4 Hrs.
DLR. CODING: Basic Part No. Code:
Step 1 - 1007 67
Step 2 - 4635 41
Step 3 - 4602 67
Step 4 - 7040110 07
Step 5 - 7029038 57
Step 6 - 7000396 35
Step 7 - 18125 63
Step 8 - 4209 67
NOTE: Basic part numbers 4209, 4635 and 4602 are eligible under Powertrain Warranty Coverage.