Retained back Hyundai H1 2.0 90cv

Good to see if someone knows the problem of my Hyundai H1 is disel the engine is a 2000 90cv is 10 years old.

The problem is that when there is slope and only when it is positioned in descent when putting back it retains boats as if it were slowed but progresses very slowly gives the feeling that the hand brake was put on;
Since I smelled too much, I have already tried to avoid doing this type of maneuver, the curious thing is that in Llano nothing happens when putting back and works perfectly. Someone has any idea what could be? thank you.

Look it can be two things mainly because of the data you give us, first that the clutch is effectively spent and when putting effort, it reflects it, or that a balat is effectively stuck, now the smell of the disco is almost equal and it may be that you confuse it,