Automatic Transmission Fluid Leaks

WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

Checks	Causes
Torque Converter (1)	Inspect for damage, cracks at the lug, hub and seal welds.
Stator Shaft Front Seal (404)	Inspect for cut, wear, or damage.
A/Trans Case (13)	Inspect for porosity or damage. Inspect manual shaft seal. Inspect control wiring input sleeve seals.
A/Trans Case Extension (68)	Inspect extension seal assembly. Inspect extension to case seal.
A/Trans Fluid Pan (21)	Inspect the pan assembly for damage. Inspect gasket for damage or wear. Inspect case and pan for damage and flatness at gasket interface area.
A/Trans Front End Leaks	NOTE: The torque converter fluid seal, automatic transmission case front cover seal and clutch pressure plate should all be replaced when addressing a transmission front end leak. Automatic Transmission Case Front Cover Seal (5) Clutch Pressure Plate (9) Torque Converter Fluid Seal (2)
Cooler Lines/Coolers	Inspect and follow cooler lines to front radiator and external coolers. Some vehicles may have rear differential external and internal coolers.