Difficult to reach low range...

[landmannnn]

I hear what you are saying but I can't understand why?

It might be that the torque converter is still applying some torque to the gearbox output when in neutral. (Or the gears are locked when in P)

 

[Eric]

It might be that the torque converter is still applying some torque to the gearbox output when in neutral. (Or the gears are locked when in P)

Both those 2 seem logical, but more likely the first N option, I usually use P with the engine running.
I also think operator apprehension play a part. When I am not in a hurry, and parked on my drive and feeling quite laid back, it goes in easy.
If I am rushing and in a strange place with a trailer in tow and tense about putting low/diff lock in, or worrying about the lever pin falling out then it is sometimes difficult.

 

[Jean Mercier]

I hear what you are saying but I can't understand why?

Well, I had the same experience as @landmannnn , and I don't understand why either.

 

[Tom D]

As there is no synchro in the transfer box the gears do have to line up. If you happen to have stopped with the teeth facing each other then it won't engage. Rolling forward or back a short distance will fix this. I have also noticed that allowing the lever to move slightly side to side helps. It's tempting to push it hard away from you (RHD) to keep it diff locked as you change ratios, don't do this, it doesn't help. Just allow it to feel its own path forward or back.