What is this tool thread?

Miller L-4435 Remover
Use this tool to remove differential bearing retainer and extensions housings on all transaxles on domestic vehicles.

Miller MD-998303 Spring Compressor
Use this tool to compress the valve spring while servicing the kickdown servo in Colt vehicles equipped with automatic transaxles.
1980 thru 1989.

Miller MD-998303-2 should be part of Miller MD-998303.