JCB htd-5 travel motor gear oil?

[Tomo]

I have an jcb htd-5 that has been a great bit of kit, but does anyone know how you might go about servicing the gear oil in the travel motor’s planetary gearing? There aren’t level or drain plugs that I can see and no mention of it in the manual? Must surely need changing?

 

[Mick-the-fitter]

I thought they were drip fed from the motor at the rear, with a leak off back to tank