Lost reverse instantly. All foward gears and shifting work fine. 150,000 miles. Dropped tranny, filter clean, acclumination of very fine metal in pan in very small amount. Removed valve body no discoloration or foreign pieces. What part failed. Neighbors car. Didn't read codes first before disassembly. Can I flush torque converter and lines and cooler and replace a part or make an adjustment due to the small amount of metal that appears to be normal wear and tear?