Land Rover Repair: Stalling, landrover freelander, reverse gears

Question
I have a Landrover Freelander 1.8i(Manual Gear) and after the initial start and
drive(no problems with this part) I am having problems with 1st gear and
reverse gear where the car judders and tries to stall. This only seems to be
happening when the engine has warmed up . All other gear changes are fine.
There is also quite a loud whine coming from the engine which can be heard
inside the vehicle while driving(which I have not heard before from my
previously owned Freelander) Any Ideas on what is causing these problems?
Many Thanks.

Answer
I would say juddering when the car gets warm indicates clutch failure.  The only other possibility I can think of is that 1st and Reverse gears have a switch on them that enable the hill descent.  If the hill descent is being engaged in these gears, it would cause a juddering.  

I suspect the whining noise is unrelated to the first problem if it is constant through all gears.  Unfortunately, the symptom is too vague for me to diagnose without additional information and without being able to hear it.