Technician A says that the military gear lube classification MIL L 2105D is equivalent to API GL-5.Technician B says that API GL-3 and API GL-4 are not approved for use in current heavy truck differential carriers.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Technician A is correct because the MIL L 2105D specification is indeed equivalent to the API GL-5 specification, which is commonly used for heavy-duty differential gear oils. Technician B is also correct because API GL-3 and GL-4 lubricants are generally not approved for use in current heavy truck differential carriers due to their lower levels of extreme pressure (EP) additives compared to API GL-5, which is required for the higher load conditions experienced in these applications.