Mac's has the tool in two forms, one more expensive than the other. I got the less expensive one and it worked fine. Turns out to be a 1/2" pipe coupling welded into a big washer. But, like I said, it worked fine. By the way, when you install the seals, consider them to be like check valves. The ones on the axles should allow over pressurized wheel bearing grease to flow into the differential. At the drive shaft, it should allow over pressurized flow to go into the U joint. The transmission vents into the clutch area.