There are a number of engine options int he Jeep Grand Cherokee.
5.7 V8 Petrol
6.4 V8 Petrol Hemi
All of these engines will require the crank pulley to be removed at some point in its life time.
All of the Petrol engines have about that is normal thread “righty tight, lefty loosey”. However the Diesel engine in a reverse thread bolt. If for what ever reason you’re trying to remove the crank pulley bolt on a Diesel engine, it goes the opposite direction.
The V6 engines do offer enough room to remove the crank pulley with a crank removal tool shown in the picture or if you have a high powered impact gun you can get it in there without removing the cooling fans.
Both the V8 engines require the cooling fan to be removed. to allow the length of the bolt to come uut without damaging the fan or pushing the fan into the radiator.
Its common practice amongst DIY mechanics to place a long bar on the engine and to crank the motor. This does work but is not good practice. If you are doing it this way. It will not work on the diesel, you will break the socket or worse break the bolt or crank shaft.
If you are using this method in a V8 you must remove the cooling fan or the bolt and socket will very quickly unread on crank and damage the cooling fan.