Broken Shaft Seal May Cause Loss of Power Steering – 2020-2021 Oshkosh S-Series

November 2, 2021 NHTSA CAMPAIGN NUMBER: 21V851000

Broken Shaft Seal May Cause Loss of Power Steering

A loss of power steering assist increases the risk of a crash.


NHTSA Campaign Number: 21V851

Manufacturer Oshkosh Corporation

Components STEERING

Potential Number of Units Affected 563



Oshkosh Corporation (Oshkosh) is recalling certain 2020-2021 S-Series vehicles. A machining defect may cause pressure to build in the power steering pump and break the shaft seal, resulting in a loss of power steering assist.



Owners will inspect and replace the power steering pump as necessary. Owners may perform this work themselves or reach out to one of our service centers to perform the inspection and repair work free of charge. Owner notification letters were mailed on December 15, 2021. Owners may contact Oshkosh customer service at 1-888-686-7278.



Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to






A concern affecting safety exists in some Oshkosh S-Series Front Discharge Mixers. Trucks have been identified that may be equipped with a ZF power steering pump that might contain an internal pump rotor machining defect. The defect may cause the pump’s pressure to build and cause the pump’s shaft seal to leak, resulting in a loss of power steering assist. The leaking shaft seal can also allow hydraulic oil to enter the engine oil. This bulletin provides instruction on inspecting the power steering pump serial number and steps required if power steering pump requires replacement.


Affected Vehicles:

The affected vehicle population is Oshkosh S-Series Front Discharge Mixers produced in 2020-2021.

Units Affected: VIN 801358 – 809179

Please refer to the attached VIN list of affected vehicles.


Time Completion:

Complete the enclosed procedure for each affected truck. The time of accomplishment may vary due to a number of factors; however, the estimated time for pump inspection is 0.5 hours and the time for pump replacement is 2.5 hours.


Required Action:

Review and verify your ownership of all affected serial numbers of Oshkosh vehicles. Oshkosh records indicate that you are the owner of one or more affected trucks, a Serial Number List is enclosed. Please be reminded that it is a violation of Federal law for you to sell or lease the vehicles covered by this notification until this recall has been performed on these vehicles. Substantial civil penalties apply to violations of this law.


Parts Required:

Item Part Number Description Qty.
1 A000H951 PUMP, VANE SGL 1.95 F CCW A 1



Preparation and Inspection

1. Park truck on flat, level surface, engage parking brake, chock truck tires, and perform your company’s Lockout/Tagout procedure. If your company does not have a Lockout/Tagout procedure, follow OSHA 1910.147 and 1910.146 Confined Space as appropriate.

2. Battery Disconnect Switch
The vehicle’s BATTERY DISCONNECT switch is located on the left-hand side of the battery box. Use the battery disconnect switch when performing any maintenance so the vehicle cannot accidentally be started.

a. Turn the battery disconnect switch (Figure A, Item 1) counterclockwise so the hole on the switch aligns with the hole in the bracket (Figure A, Item 2).

b. Install the safety lockout device ring (Figure B, Item 1) through the holes on the battery disconnect switch and the bracket.

c. Install a padlock (Figure B, Item 2) onto the safety lockout device ring, lock it, and put the key in your pocket. If more than one person is working on the vehicle, each person must install his or her own padlock.

d. Allow truck to cool before inspecting/replacing power steering pump.

Pump Inspection

3. Locate power steering pump on right-hand side of engine, see Figure 1. The pump serial number is stamped on pump body, closest to the engine block. Use a mirror to verify pump serial number on pump body.

If the pump serial number matches one of the serial numbers in Table 1 continue to Step 4.

If the pump serial number does not match one of the serial numbers in Table 1 pump inspection is complete and no further action is required.


Chronology :

In August 2021, Oshkosh was contacted by its supplier, ZF, about a potential issue affecting certain power steering pumps. ZF noted that another OEM, Spartan Fire, had conducted a safety recall on a power steering pump with a similar part number. Oshkosh initiated an internal review of its experience with the power steering pump at issue and noted that while it had received a limited number of warranty claims, the majority of those claims involved failures that occurred within the first approximately five months of vehicle use. Based on this data and information from the supplier that any affected parts would have been isolated to within the first five months of vehicle use, it was believed that any issues with the power steering pumps in Oshkosh vehicles were isolated to early use of the vehicle and had already been addressed in the field. In late September 2021, Oshkosh received a report of two trucks that experienced a power steering pump failure. Upon further investigation, Oshkosh determined that these vehicles were approximately one year old at the time of the failure. Since the production date of these two vehicles fell well-outside of the timeline that suggested the parts issue was isolated to early use of the vehicle, Oshkosh began to investigate further. Oshkosh found that all related warranty claims involved reports of hydraulic power steering oil falling onto engine oil with no reports indicating an actual loss of steering assist while driving. On October 27, 2021, NHTSA contacted Oshkosh about whether it would be submitting a recall report related to this issue. Oshkosh’s investigation was already ongoing and on November 1, 2021, Oshkosh decided to initiate a safety recall to address vehicles in the field.


2 Affected Products




9 Associated Documents

Remedy Instructions and TSB

RCRIT-21V851-5576.pdf 2655.468KB



Defect Notice 573 Report

RCLRPT-21V851-4623.PDF 214.458KB



Recall Acknowledgement

RCAK-21V851-3330.pdf 703.377KB



Recall 573 Report – December 15, 2021

RCLRPT-21V851-9259.PDF 214.477KB



Recall 573 Report – December 7, 2021

RCLRPT-21V851-5770.PDF 214.478KB



Recall Quarterly Report #1, 2021-4

RCLQRT-21V851-0333.PDF 211.224KB



Recall Quarterly Report #2, 2022-1

RCLQRT-21V851-6626.PDF 211.224KB



Recall Quarterly Report #3, 2022-2

RCLQRT-21V851-4739.PDF 211.313KB



Recall Quarterly Report #4, 2022-3

RCLQRT-21V851-1969.PDF 211.416KB



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Last update on 2023-11-13 / Affiliate links / Images from Amazon Product Advertising API

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