lubricant for front/rear axles - differentials

[Tibiko]

does anybody knows if periodical lube change is required for rear/front differentials. according to the manual they are lubricated for life, however a tech told me that they require regular oil changes similar with tranny/transfer case. I do not trust his expertise though.
I know that the axles require lube changes only if serviced or after being submersed in water

thanks

 

[PartTimer]

The front is easy to change, I have the lube for the rear but it also calls for a "Friction modifier" as well.

 

[rwinch]

Changing lubricants is always recommended. Changing them more often than not does not hurt anything, except the wallet, but then it may prevent future repairs that will in the long run cost more.

I use all synthetics; brake, power steering, tranny, transfer, front and rear diffs. I try to change them every 1-2 years, which I just consider insurance.

PartTimer is correct about the "friction Modifier" for the rear, but also note that the rear takes a heavier weight lube than the front.