In applications where gearboxes operate under conditions that do not permit the use of liquid lubrication, solid lubrication is necessary to reduce friction and wear. However, the ability of solid lubrication for convective heat removal is limited, increasing the risk of thermal failure modes. Molybdenum disulfide (MoS2), a solid lubricant used in lacquers, powders, or physical vapour deposition (PVD) coatings, reduces friction and wear, but its use has been limited to low mechanical loads. This study investigates the potential of triboactive coatings, with the incorporation of the triboactive elements Mo, W and S in wear-resistant CrAlN coatings, to enable the in situ formation of solid lubricants in highly loaded cylindrical gear contacts. Different coating architectures are developed and evaluated through tribological testing. The reduction in friction caused by the in situ formation of solid lubricant is demonstrated using a pin-on-disk and twin-disk tribometer, and validated for cylindrical gears using a back-to-back gear efficiency test rig. Investigations on the influence of the gear geometry also show potential for reducing frictional heat and improving convective heat transfer.