I'd keep the tranny in neutral just because.
no precautions, except the common sense ones.. where safety glasses, I recommend gloves also. there won't be any damage to the engine, unless the bolt is extra stubborn and the gun rotates the engine backwards... that's not necessarily a good thing. However, a good blast of reverse torque should loosen the crank bolt pretty quickly.
Are there any special precautions that need to be taken before using
> an impact wrench on the crankshaft pulley bolt, ie. shifting the
> transmission from PARK to NEUTRAL? Is there any possible damage to
> internal engine or transmission components that can occur from using
> an impact on the crank pulley?
>
> Thanks for the help.
>
> Rob.