You may want to shop for an electric impact. I don't think they have the oof that an air impact does, but you don't have to get an air compressor. I was given an old kinda crappy one. But I put new brushes in it and for 25 years it just keeps doing what ever I ask of it.
Or just pop by your local tire store with the alt in hand. Most tire stores would be happy to pop it off for you... ' cause you might remember them when you need to buy tires.....

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Thanx,
Alberta Luthier
1983 300CD ('Stinky')155k miles, 2.47 diff, EGR removed, AAZ injectors with 265 nozzles from Sean,and vogtland lowering springs.
1984 300SD ('Old Blue')150k Klicks from Japan originally, came with rear head rests, no sunroof and never had an EGR