Gramps (NSW) replied:

I'd prefer to do them before setting off. Too much trouble doing them along the way. Much better things to do.

Steve from Top End Explorer Tours replied:

ps,not looking forward to that diff oil in my hair :)

Yeah it will muck up your finger nail polish as well. LOL

Unless I get water in the oils I change mine every 40k, But I check them regularly.

As for keeping your wheel arches clean paint them Black.

Cheers Steve.

MEMBER - Darian (SA) replied:

Join the club Lyndon - as well as saving $ you will get some practical experience in solving issues that may arise under there, while in the bush. Changing engine oil mid trip is not hard - and you don't need to pollute the environment either. I do the diffs and transmissions etc. largely as the book indicates - if that is going to happen mid trip, I do them just prior. I just keep an eye on drive belts and hoses and carry spares. Re the timing belt - that is done as the book, or much earlier !!

guzzi replied:

Mate for a trip like that ( you lucky bugger) I'd be changing ALL the fluids, filters and coolants, greasing your wheel bearings and uni joints.
Id also be making up a kit of all your hoses, belts and filters and taking them with you.
Id also be inclined to have a knowledgeable 4x4 type mechanic give it the once over if you are heading off into the more remote areas.
Good luck with the preparations.

nowimnumberone replied:

as a mechanic in a 4wd service centre i cant tell you how often i have to change diff/gearbox oil every 40000ks when it still looks as good as the day i put it in.
why do i change it ?
while under warranty the service book says it has to be done.
so we do it.
after a car is out of warranty and we service them we always check levels and condition.
if there off colour we change if not we leave and put on the service sticker there due a change next service.
if your vehicle has done 50000ks toyota should have done them at 40000ks i wouldnt bother changing them yet.
no time like now to get under there and learn how to check them for when it is time to change them.
loosen the plug in all check points dip your finger in and if it looks clean put the plpug back in and check again in another 5000ks.
if you dont want diff oil in your hain make sure you take the filler plug out before you pull out the drain plug lol
cheers