GM P/N United States 12378514, GM P/N Canada 88901045 Hypoid Gear Oil has ultraviolet dye already included within the oil.

Drain and fill the unit with new oil before using the black light, when inspecting for leaks. Ultraviolet dye is not approved for continued use.

Restricted or damaged breather plug assembly

Replace the breather plug as required.

Worn, scored, or missing drain and/or fill plug sealing washers

Install new sealing washers and tighten the plugs per specifications.

Worn or damaged driven shaft oil seal

Replace the driven shaft oil seal and output flange as required.

Cut or damaged drive shaft housing O-ring seal

Replace the O-ring seal as required.

Worn wheel drive shaft oil seals

Worn or damaged wheel drive shaft oil seals may be detected by a fluid leak at the breather plug area on the bottom of the case. A red colored fluid indicates a transaxle fluid leak and a clear or brown colored fluid indicates a hypoid gear oil leak.

Replace the oil seals and the drive/driven shafts as required.

Cut or damaged transaxle assembly-to-transfer case seal

Replace the seal as required.

Cases or housings porosity or leaking seal surfaces

Replace the cases and housings as required and reseal the assembly.