Use the same oil and follow the steps below:
- Use 20% of new oil capacity;
- Turn the gearbox for 1 hour;
- Them turn off the machine
- Change the oil again, for at least 20% of capacity again;
- Turn the machine for 1 hour again;
- Them flow away the rest of oi;
- And complete with new oil until the working level (use the gear line).
I recommend use Mobilgear 600XP (ISO VG at the machine indicated)
The best for micro pitting wear.