ATP, Inc. started on July 1, 1955 as Automatic Transmission Parts to provide automatic transmission replacement parts for installers. At that time no aftermarket manufacturers were making those parts. To this day ATP is still a privately held company. ATP is based in a northern suburb of Chicago, Illinois. Their 92,000 square foot facility gives them the ability to turn orders around quickly and they routinely achieve a fill rate of more than 98%. ATP does not just sell transmission filters; they sell a complete line of transmission parts. In 1999 a new logo was adopted and the company name was changed to ATP Professional Auto Parts. It was at this time that ATP diversified and began making a wider range of replacement parts, not just automatic transmission parts. ATP introduced Graywerks in 2001, which specialized in exhaust manifolds, harmonic balancers, timing covers, and engine and transmission parts. ATP's current product line includes automatic transmission filter kits, repair kits, exhaust and manifold kits, harmonic balancers, timing covers, cables, flywheel and ring gears, interior vent filters and chemicals. The company relocated to Elk Grove Village, Illinois in 2009.