Repair services often include diagnostics (DGA, electrical tests, SFRA), de-tanking, inspection of core and windings, drying and reconditioning of insulation, rewinding if necessary, and replacement of bushings, gaskets, and OLTC components. Oil is filtered or replaced, and the cooling system is cleaned and tested. Final routine tests verify ratio, impedance, losses, and insulation strength. Many service providers also offer on-site commissioning, warranty on repairs, and recommendations for monitoring to extend remaining life.