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TECHNICAL SERVICE BULLETIN
Single Rear Wheel - Boom/Hum/Moan Noise Or Vibration From
Rear While Driving At Highway Speeds

21-2064
09 March
2021

This bulletin supersedes 20-2214. Reason for update: Not Applicable
Model:
Ford
2015-2021 Transit
Summary
This article supersedes TSB 20-2214 to update the vehicle model years affected, Title, Issue, and Action.
Issue: Some 2015–2021 Transit vehicles equipped with rear wheel drive (RWD), single rear wheel
(SRW), and a U-joint at the transmission flange and rear driveshaft may experience a boom/hum/moan
noise or vibration from the rear while driving. This noise or vibration is more noticeable at highway speeds
(112-121 km/h [70–75 mph] for 4.10 axle ratio, 121-128 km/h [75-80 mph] for 3.73 axle ratio, and 136-145
km/h [85-90 mph] for 3.31 axle ratio) and may also be present to a lesser degree at roughly half of those
speeds. This may be due to a 2nd order driveline frequency transmitted through the rear driveshaft, rear
axle and into the body through the leaf springs. To correct the condition, follow the Service Procedure to
install a driveshaft torsional damper.
Action: Follow the Service Procedure steps to correct the condition on vehicles that meet all of the
following criteria:
• 2015-2021 Transit
• SRW
• RWD
• Boom/hum/moan noise or vibration at highway speeds
• U-joint at the transmission flange and driveshaft
NOTE: Part quantity refers to the number of that service part number required, which may be
different than the number of individual pieces. Service part numbers contain 1 piece unless
otherwise stated. "As Needed" indicates the part is required but the number may vary or is not a
whole number; parts can be billed out as non-whole numbers, including less than 1.
Parts
Part Number

Description

LK4Z-4A263-C Torsional Damper Kit

Quantity
1

Special Tool(s)
Mastertech® Series MTS 4000 Driveline Balance and NVH Analyzer
Warranty Status: Eligible under provisions of New Vehicle Limited Warranty (NVLW)/Service Part
Warranty (SPW)/Special Service Part (SSP)/Extended Service Plan (ESP) coverage. Limits/policies/prior
approvals are not altered by a TSB. NVLW/SPW/SSP/ESP coverage limits are determined by the
identified causal part and verified using the OASIS part coverage tool.
Labor Times

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Description

Operation
No.

Time

2015-2021 Transit: Diagnose, Inspect The Rear Driveshaft, Install A Driveshaft
Torsional Damper And Torsion Damper Shield Includes Time To Remove The
Pinion Nose Damper If Equipped (Do Not Use With Any Other Labor Operations
Outside Of This Article)

212064A

1.1
Hrs.

2020-2021 Transit Additional Time To Remove And Install Running Boards When
Necessary (Can Be Claimed With Operation A)

212064B

0.3
Hrs.

Repair/Claim Coding
Causal Part:

4A263

Condition Code: D9

Service Procedure
NOTE: This article does not apply to dual rear wheel (DRW) vehicles.
1. Using the Mastertech® Series MTS 4000 Driveline Balance and NVH Analyzer (Vetronix) or equivalent,
analyze the noise or vibration to determine the order. Does analysis identify the concern as a 2nd order
driveline vibration?
(1). Yes - proceed to Step 2.
(2). No - this article does not apply. Refer to Workshop Manual (WSM), Section 205-01.
2. Inspect the rear driveshaft, driveshaft joints, driveshaft center bearing(s) and slip yoke splines for
damage or wear. Refer to WSM, Section 205-01. Is there evidence of damage or wear to the driveshaft,
driveshaft U-joints or slip yoke splines?
(1). Yes - this article does not apply. Refer to WSM, Section 205-01.
(2). No - proceed to Step 3.
3. Mark the pinion flange and rear driveshaft U-joint to enable correct indexing of the driveshaft during
installation. Refer to WSM, Section 205-01.
4. If equipped, remove and discard the pinion nose damper from the axle assembly.
5. Remove and discard the driveshaft to axle pinion flange bolts. With a suitable strap, support the
driveshaft so there is no undue stress applied to the rear driveshaft-to-transmission output flange joint or
rear driveshaft center bearing(s). Refer to WSM, Section 205-01 Removal and Installation, Rear
Driveshaft.
NOTE: The maximum articulation of any U-joint is 10 degrees. If the driveshaft U-joint is articulated
further than the maximum allowable degrees damage may occur.
6. Inspect the pinion flange to driveshaft mating surface for any debris or excessive rust and clean as
necessary.
7. Install the driveshaft torsional damper on the axle pinion flange. (Figure 1)
Figure 1

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8. Align the index-mark on the driveshaft and rear drive pinion flange and reinstall the driveshaft ensuring
the driveshaft fits securely over the raised flange on the torsional damper.
(1). Install the driveshaft attaching bolts and tighten to 115 Nm (85 lb-ft) Refer to WSM, Section 20501. (Figure 1)
9. Install the torsion damper shield to the right side of the axle assembly near the pinion using the existing
holes in the axle housing. Use the 2 bolts and the nut supplied in the torsional damper kit. Tighten to 48
Nm (35 lb-ft). (Figure 2)
Figure 2

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© 2021 Ford Motor Company
All rights reserved.
NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge,
tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or
provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do
not assume that a condition described affects your car or truck. Contact a Ford or Lincoln dealership to determine whether the
Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended
Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was
current at the time of printing. Ford Motor Company reserves the right to supersede this information with updates. The most recent
information is available through Ford Motor Company's on-line technical resources.

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