National 710978 Automatic Transmission Output Shaft Seal - Left

Automatic Transmission Output Shaft Seal

National 710978 is an automatic transmission output shaft seal built for left-side applications across a wide range of Hyundai and Kia vehicles. It uses a counter-clockwise spiral lip design and polyacrylate construction to support sealing performance in transmission service.

Key Features

• Polyacrylate seal material for transmission fluid sealing applications.
• Counter-clockwise spiral lip design for controlled sealing action.
• Metric dimensions for accurate service replacement.
• National 710978 is part of the 710900 series.
• Fits a broad range of Hyundai Elantra, Tucson, and Kia Forte applications.

Detailed Description

This National output shaft seal is engineered as an oil seal for automatic transmission service. The listed dimensions include a 61.2 mm outside diameter, 61.0 mm housing bore, and 41.0 mm shaft size, helping confirm fitment during repair planning. Compatible applications include Fits 2007-2019 Hyundai Elantra, Left; Fits 2005-2014 Hyundai Tucson, Left; and Fits 2010-2019 Kia Forte, Left. The part number 710978 is also referenced in service searches for Hyundai and Kia transmission sealing repairs.

National has supplied sealing solutions for more than 75 years and continues to develop products for current vehicle service needs. This part cross-references ATP TO-67 and Timken SL260121 for the same application.

Common Uses

• Replacing a leaking transmission output shaft seal.
• Restoring fluid retention at the transmission shaft interface.
• Addressing seepage around the output shaft area.
• Supporting repair of worn or hardened seal surfaces.
• Servicing left-side transmission applications on Hyundai and Kia models.

Installation Notes

Verify shaft diameter, housing bore, and transmission application before installation. Confirm the transmission type listed in the fitment notes where applicable, including Hyundai A5GF1 and A5HF1 references. Clean the sealing surface thoroughly and inspect the shaft for wear or scoring before installing the new seal.

Quality Assurance

National is recognized for premium sealing solutions and long-standing industry experience. Part number 710978 is built to meet the dimensional and design requirements listed for the specified applications.