Abstract: A heavy duty lubricating composition for lubricating metal rubbing surfaces, such as journal bearings in rock bits, is provided that forms a solid as a result of increased temperature at the areas of highest shear rate or highest loading in the bearing. The solid reverts to its original state within the carrier fluid when passing into areas of lower temperature. The composition comprises a substantially uniform dispersion within a carrier fluid of a solid additive having decreasing solubility/dispersibility in the carrier fluid as temperature increases, an additive capable of forming with the carrier fluid viscous lubricating solutions in water, and an extreme pressure agent having a high temperature of activation with the bearing materials.