2021 Hyundai Automatic Transaxle ATF Leak TSB 21-AT-017H

Symptoms

Owners of certain 2021 Hyundai Sonata, Santa Fe, and 2022 Tucson vehicles may notice an automatic transmission fluid (ATF) leak originating from the rear cover of the transaxle. This leak is typically visible near the pressure port check plug on the transmission and indicates a potential issue with the transaxle's casting.

Important Warning

Hyundai explicitly states a critical caution regarding the repair for this automatic transaxle ATF leak:

"DO NOT replace the rear cover of the automatic transaxle. The rear cover controls the end-play on the disk set and clutch pack. If the selectable spacers are not changed to correct the end play for the new rear cover, the durability of the transmission could be affected."

This means that attempting to repair only the rear cover could lead to further transmission damage and compromise the long-term reliability of the component. The proper repair involves replacing the entire transaxle assembly.

Repair Procedure Summary

If your vehicle exhibits a Hyundai Tucson ATF leak or a leak from a similar model as described in TSB 21-AT-017H, the service procedure involves replacing the entire automatic transaxle assembly. Technicians are instructed to:

1. Confirm the transmission is leaking from the rear cover, specifically near the pressure port check plug.
2. Replace the complete automatic transaxle assembly. This must be done according to the applicable vehicle shop manual, ensuring all components are correctly installed.
3. After replacement, check the automatic transmission fluid (ATF) level and add SP4-M ATF (part number 00232-19057) as necessary, following the vehicle's shop manual specifications.

This comprehensive approach ensures that the underlying issue of the porous casting causing the Hyundai Tucson ATF leak is fully resolved and the transmission's integrity is maintained.

Required Parts

Replacing the automatic transaxle assembly requires specific part numbers depending on the vehicle model, transmission type, and drivetrain configuration. The following are the relevant part numbers for the transaxle assemblies:

• Sonata (DN8A) 1.6T 2WD 8AT Smartstream: 45000-4G621
• Sonata (DN8A) 2.5L 2WD 8AT Smartstream: 45000-4G610, 45000-4G611
• Santa Fe (TMA) 2.5L 2WD A8MF1: 45000-4GDX0
• Santa Fe (TMA) 2.5L 4WD A8MF1: 45000-4GDX5
• Tucson (NX4A) 2.5L 2WD A8MF1: 45000-4GDM0, 45000-4GDN0
• Tucson (NX4A) 2.5L 4WD A8MF1: 45000-4GDM5, 45000-4GDN5

Additionally, the specified automatic transmission fluid is SP4-M, with part number 00232-19057.

Warranty Information

For repairs performed under TSB 21-AT-017H, warranty claims should be submitted using the Campaign Claim Entry Screen. The following operation codes (Op Codes), causal part codes, nature code, and cause code are associated with this repair:

• Sonata (DN8A) 1.6T: Op Code 10DA28R0, Causal Part 45000-4G621
• Sonata (DN8A) 2.5L: Op Code 10DA28R1, Causal Part 45000-4G610, 45000-4G611
• Santa Fe (TMA) 2WD: Op Code 10DA28R2, Causal Part 45000-4GDX0
• Santa Fe (TMA) 4WD: Op Code 10DA28R3, Causal Part 45000-4GDX5
• Tucson (NX4A) 2WD: Op Code 10DA28R4 or 10DA28R6, Causal Part 45000-4GDM0, 45000-4GDN0
• Tucson (NX4A) 4WD: Op Code 10DA28R5, Causal Part 45000-4GDM5, 45000-4GDN5

All repairs have an estimated operation time (Op Time) ranging from 3.3 to 3.8 hours. The Nature Code for this issue is T83, and the Cause Code is ZZ3. If additional parts not covered by this TSB are found to be necessary and are under warranty, a separate claim should be submitted. For out-of-warranty parts, prior approval for goodwill consideration may be required.

Owner Action

If you own a 2021 Hyundai Sonata, Santa Fe, or Tucson manufactured within the specified dates and suspect an automatic transmission fluid leak, especially a Hyundai Tucson ATF leak, it is recommended to contact your authorized Hyundai dealer. They can diagnose the issue and perform the necessary transaxle replacement as outlined in TSB 21-AT-017H. Ensure to mention any visible leaks or unusual transmission behavior.

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Source: NHTSA ID: 10203274