Although really well engineered drives, if not over engineered...they have one or two weak points.
The most common of which are;
water ingress through the bloody oil drain screw seal. I used to silicone over the plug after each oil change
The trim pump (if original) has a habit of passing at the valves inside the pump. This means the drive will slowly creep down, at best...and fall down at worst.
Check the stare of rhe cone clutch too, if you are able. Test by making sure it doesn’t slip or delay going in and out of gear after it’s warmed up and been running fast. These are a pain to do at best, and expensive to do, if by a dealer, at worst.
Oh and the pins you need to take out to remove the drive can be stubborn if not out annually.
