# Service bulletin SSM 51821

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10240575
- Published by NHTSA: 2023\-08\-10
- Manufacturer's number: SSM 51821
- Manufacturer's date: 2023\-08\-01
- NHTSA component: POWER TRAIN:TRANSFER CASE \(4\-WHEEL DRIVE\); SUSPENSION:REAR:AXLE:NON\-POWERED AXLE ASSEMBLY; POWER TRAIN

## NHTSA's summary

Some 2020\-2021 Explorer/Aviator/Police Interceptor Utility vehicles equipped with AWD may exhibit a binding or shudder sensation while turning and/or while accelerating from low speeds. The concern may also be described as a grinding and/or chatter noise. If the Workshop Manual \(WSM\) leads to replacement of the rear axle, inspect the differential for damage and differential fluid for metallic chunks in the fluid. Note that some metallic flake in the fluid and/or discoloration is normal and the rear axle should not be replaced for it. If no damage is found to the rear differential, it is not recommended to replace the rear axle assembly. Instead, refer to the Symptom Charts in WSM, Section 307\-07A for further diagnosis of the transfer case.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2023/MC-10240575-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2023/MC-10240575-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Suspension, Transmission and driveline, Transfer case

## Vehicles listed

- 2020 to 2021 FORD EXPLORER
- 2020 to 2021 FORD EXPLORER POLICE INTERCEPT
- 2020 to 2021 LINCOLN AVIATOR

JSON: [/v1/bulletins/10240575](/v1/bulletins/10240575)

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