I have a 55 with a 265 and powerglide. The starter works great when the engine is cold. It drags or turns very slowly once the engine is hot. Let it cool and it spins fast and starts right up. It is about to go to the shop to have the oil pan pulled and cleaned. I would like to address the starter issue while I have a lift. What is the common cause for it dragging? Brushes or something else?