MG Car Repair: Non MG, holden vr, oil service

Question
sorry about this i can totally understand if you cannot answer this but there isn't a category for my car and every other category experts are either maxed out or on vacation.
I live in Australia and have a 1993 Holden VR 3.8 V6 and got it tuned and they mentioned that i needed a differential oil service but was told by a friend that most cars never really need one just wanted to know whether that is true or not because if i don't really have to spend money on it that would be good.
P.S. i have had no problems with the car but they say i need it done wonderingwhether or not they are just trying to scam me.

thanks very much, and sorry for the fact that this is a non MG topic.

Answer
Hi Ben,
You can not ware oil out, all you can do is contaminate it. So if you have run through deep water or have never changed it, or you don't know the true history of the vehicle, it would not hurt to change it.

But rear end differential oil does not normally need changing like engine oil except over a long period of time and use. Be sure you use a Hypoid type oil if you change it. This is true of any car or truck. If the vehicle has some kind of limited slip, it requires a special type of oil and you would need to refer to the manufactures recommendation.

I hope this helps,
Howard