Door handle stiff / gets stuck

[CoffeeCake]

A multi point for handle is very hard to operate. If I use force, I can get it going but otherwise it feels like it's stuck. This is with the door open. I have tried replacing the handle with a new one and that has not made any difference. Linking a video so you can see what is happening. Thanks in advance.

 

[crank39]

The gearbox is failing and will ultimately need replacing, with the handle pushed down spray some WD it the latch and see if it makes a difference, won't fix it but if it makes it better then you know you'll need a gearbox

 

[CoffeeCake]

I have tried spraying multiple times everywhere..latches and all openings. Doesn't make a difference. Is it easy to replace the gearbox?

 

[crank39]

Yes dead easy but you'll need to identify the make of the mechanism first, look up and down the strip for any makers names, the only head start I can give you are the dimensions, backset is 45mm and PZ is 92mm

 

[CoffeeCake]

Thank you. It is a FUHR. Is the offset 45mm or 35mm? Pic below.

 

[crank39]

Ok so it's a FUHR. The tape measure is irrelevant as we don't need the complete locking strip, just the gearbox and as I've said will be 45mm backset and the PZ will be 92mm, with those measurements you can Google for FUHR gearbox, there are a few versions so best to remove your mechanism from the door and match it up online