<p>The transient response of a Thermo-Elastohydrodynamic Lubrication (TEHL) contact, comprising a stationary surface with a single groove traversed by a rolling/sliding counter-body, is analysed using Computational Fluid Dynamics coupled with a structural solver. The developed model resolves the transient thermo-mechanical behaviour of TEHL line contacts with surface irregularities, capturing the load fluctuations induced by the groove and providing detailed insight into the evolution of pressure, temperature, Von Mises stress, and film thickness. The influence of groove geometry (depth and width), system equivalent mass, and slide-roll ratio (SRR) on these quantities is examined. The results demonstrate that the passage of the groove amplifies shear heating at the inlet and induces significant pressure perturbations, leading to localised film thinning near the groove edges. Whilst increasing groove depth intensifies pressure spikes and stress concentrations, wider grooves attenuate these fluctuations by enhancing lubricant entrapment and facilitating a more gradual hydrodynamic pressure recovery. These effects are most pronounced under near-rolling conditions (low SRR). By contrast, variations in system equivalent mass were found to have a negligible influence on the local pressure and temperature perturbations associated with the passage of a single groove.</p>