National 710636 Automatic Transmission Extension Housing Seal - Transmission Extension Housing To Drive Shaft

Automatic Transmission Extension Housing Seal for GM Trucks and SUVs

National 710636 is an automatic transmission extension housing seal built for the transmission extension housing to drive shaft location on a wide range of Chevrolet, GMC, and Cadillac applications. It uses a fluoro-elastomer sealing material and a counter-clockwise spiral lip design to help maintain a consistent seal at the output area.

With dimensions of 1.886 in. inside diameter, 2.705 in. outside diameter, and 0.350 in. width, this seal is sized for the specified housing bore and shaft measurements. National 710636 is a direct-fit oil seal for service work on Silverado, Sierra, Tahoe, Yukon, Escalade, and related GM platforms.

Key Features

• Automatic transmission extension housing seal for the transmission extension housing to drive shaft position
• Fluoro-elastomer construction for sealing performance in transmission service
• Counter-clockwise spiral lip design
• Inside diameter: 1.886 in. (47.904 mm)
• Outside diameter: 2.705 in. (68.700 mm)
• Width: 0.350 in. (8.890 mm)
• Housing bore: 2.697 in. (68.504 mm)
• National part number 710636

Detailed Description

National 710636 is an oil seal for the automatic transmission extension housing, engineered around the shaft and bore dimensions listed for the application. The fluoro-elastomer material is selected for sealing service in transmission environments, while the counter-clockwise spiral lip design supports controlled sealing at the output shaft area. National has focused on sealing solutions for more than 75 years, and this part reflects that experience in a service replacement format. This part cross-references Gates 18860 for the same application.

Use National 710636 when servicing GM trucks and SUVs such as Chevrolet Silverado 1500, Silverado 2500 HD, Silverado 3500 HD, Tahoe, GMC Sierra 1500, Sierra 2500 HD, Sierra 3500 HD, Yukon, and Cadillac Escalade applications listed below. The part number 710636 is also referenced in interchange data for OE-style replacement matching.

What This Seal Helps Address

• Transmission fluid leakage at the extension housing
• Seepage around the drive shaft output area
• Seal wear from age, heat, and transmission fluid exposure
• Service replacement needs during transmission maintenance
• Output seal issues on Silverado, Sierra, Tahoe, Yukon, and Escalade applications

Installation Notes and Tips

Verify the shaft diameter, housing bore, and seal width before installation. Clean the extension housing and shaft sealing surface thoroughly, and inspect for grooves, scoring, or contamination that could affect sealing. Confirm the seal orientation matches the transmission output application before pressing it into place. National 710636 is listed for the transmission extension housing to drive shaft position on the vehicles shown in the fitment data.

• Fits 2009-2019 Chevrolet Silverado 1500, Transmission Extension Housing To Drive Shaft
• Fits 2019 Chevrolet Silverado 1500 LD, Transmission Extension Housing To Drive Shaft
• Fits 2007-2019 Chevrolet Silverado 2500 HD, Transmission Extension Housing To Drive Shaft
• Fits 2007-2019 Chevrolet Silverado 3500 HD, Transmission Extension Housing To Drive Shaft
• Fits 2008-2019 Chevrolet Tahoe, Transmission Extension Housing To Drive Shaft
• Fits 2007-2019 GMC Sierra 1500, Transmission Extension Housing To Drive Shaft
• Fits 2019 GMC Sierra 1500 Limited, Transmission Extension Housing To Drive Shaft
• Fits 2007-2019 GMC Sierra 2500 HD, Transmission Extension Housing To Drive Shaft
• Fits 2007-2019 GMC Sierra 3500 HD, Transmission Extension Housing To Drive Shaft
• Fits 2008-2019 GMC Yukon, Transmission Extension Housing To Drive Shaft
• Fits 2015-2019 GMC Yukon XL, Transmission Extension Housing To Drive Shaft
• Fits 2007-2014 Cadillac Escalade, Transmission Extension Housing To Drive Shaft
• Fits 2008-2014 Cadillac Escalade ESV, Transmission Extension Housing To Drive Shaft
• Fits 2008-2014 Chevrolet Suburban 1500, Transmission Extension Housing To Drive Shaft
• Fits 2009-2013 Chevrolet Avalanche, Transmission Extension Housing To Drive Shaft
• Fits 2008-2013 Chevrolet Suburban 2500, Transmission Extension Housing To Drive Shaft
• Fits 2008-2014 GMC Yukon XL 1500, Transmission Extension Housing To Drive Shaft
• Fits 2008-2013 GMC Yukon XL 2500, Transmission Extension Housing To Drive Shaft

Quality Assurance

National is a long-established sealing brand with a focus on premium sealing solutions and ongoing design updates for modern vehicles. National 710636 is built to meet the dimensional and material requirements listed for the application.