The Gulfstream IV Structural Repair Manual is very specific on rivet substitution i.e.: It is not permissible to substitute a mechanical fastener in place of a solid fastener. Check all references to assure correct fastener installation.
Earlier this year, Honeywell released a Service Bulletin that introduced an improved gearbox cover and hydrodynamic carbon face seal to reduce oil leaks.
Flight crews and maintenance personnel need to come together and discuss how and when to properly service the oil, creating a means to log the addition of oil and discussing the responsibilities of ground personnel service when the aircraft is away from home.
When a squawk appears intermittently, valuable clues may be left out when communicating the details. Use your Smartphone to grab the details.