Makita combi drill chuck

Hi

I recently purchased a makita 18v drill and impact driver combi set. The chuck tightens with a series of small clicks but in the last few days it tightens still with a series of small clicks but now gives a quarter turn or so as it’s being tightened. So you get a series of clicks as it tightens then a sudden give and the chuck turns freely for a quarter turn or so then catches again and continues tightening with a series of clicks. The clicks fell like a solid racket but the give as it tightens feels wrong to me. Does anyone have any experience of this. 

The other problem I have had is that if I drive a screw in with the combi drill then stop and put it into reverse and pull the trigger to back the same screw out it makes a nasty noise as if some gears were crunching and doesn’t transmit any power to the screw driver bit. If I take my finger off the trigger and then put the power back on it engages as normal. Any advice would be appreciated.