Hi looking for some advice on oil. I have a 2015 fiat panda 4x4 twinair. I am going to change the oil in the drive transmission idler unit (PTU) the hand book says use gl5 75w 85 synthetic Tutela transmission multiaxle oil. On the face of it this the same spec as the rear diff oil Tutela transmission cross. but has anyone got any advice if it would be fine to use another oil of the same spec. Normally I would not be too concerned but modern engine's and drive trains seem to be very fussy. Thanks in advance for any help or advice.