Gremlins in my gearbox

[rayncc]

Since the day I got my E30 M40 (manual), the Reverse gear has always been (very) difficult to engage. Although I read that this is deemed normal for this type of car, however, mine has a puzzling problem which my mechanic has no clue on the actual cause.The problem : Every morning, or during every cold start any time of the day, upon engaging Reverse and disengaging it back to neutral after reversing the car, the gear stick would have lots of free play i.e. there was completely no resistance when I push the gear stick from centre towards the leftmost if I want to re-engage Reverse. This makes engaging 1st gear very tricky as I will risk slotting into Reverse.However after driving for some 10 minute or so, the problem will disappear, meaning that I regained the usual tension required to push the gear stick to the leftmost to engage Reverse. This means the problems will cure itself after sufficient heat-up.Does anyone ever encountered such peculiar symptom? Can the many sifus out there have any idea what could be the most likely problem, or whether it can be resolved without changing the gearbox?Regards,