Land Rover Repair: Disco2 V8 Auto Box, gearbox manufacturer, gearbox oil

Question
Hello John,
I had my Disco2 gearbox oil checked and topped up a short while ago at 170 000 km and it was working fine. It still works well selecting all gears properly when cold or on the freeway but when driving in hot weather in stop/start traffic in the afternoons, as soon as I get back into the free flowing traffic on the freeway, it does not select 4th or 5th gear. The next morning all is well again in the cool weather. What could it be please?
Regards,
Paul.

Answer
Whatever it is, it is almost certainly within the gearbox.  I'd suggest you remove it and send it to a ZF agent for overhaul(ZF is the gearbox manufacturer, not Land Rover)

It's going to cost less to fix it now, while it's basically working, than if you wait till something blows up.  There are no external causes for the problem you describe.