Am I getting scammed by my main dealer?

raptor2004

My F82 BMW M4 Competition is due a minor service and my local main dealer told me I need to change the oil in on the rear axle differential. I have never heard of such a thing, a minor service is usually just the engine oil, oil filter and microfilter. 

I did a bit of research only the only cars that have a rear differential are generally 4x4 cars so why is my main dealer charging me for this?

Looking at the service history on the iDrive, there is no mention of the rear axle differential oil having been changed so why suddenly now? Does my car actually have a differential and if so, why does an ordinary coupe car need one?

ontheroad1970

That's a very detailed rhetorical question

Ayr_Rage

Haha, if it hasn't got a differential you are in serious trouble, time for some research about axles and drivetrains @raptor2004 !

You car is RWD so that is where the differential lives.

As for the need to change the oil, look at the schedule, it may be time related rather mileage so therefore could coincide with either a major or minor service and this could be the first time it is required.

In all honesty, you seem to have very little idea about the mechanics of your (or any other) car.

Edit : Having had a look at your other posts on various motoring issues, is this real or just a wind-up ?

fatbelly

That sounds like you have a very good dealer who wants to look after your car. I suggest you do what they say

That's a very complex car with high maintenance costs and you need to budget accordingly

Goudy

A front wheel drive car has it's differential inside the gearbox, so it shares the gearbox oil.

Rear wheel drive cars have their differential on the rear axle, away from the gearbox, so have their own bath of oil.

As it's a performance car, a lot of power will go through it, heating the oil up which tends to cause it to breakdown over time.
The oil not only lubricates, it helps cool the moving parts inside as well.

It would almost certainly have some form of limited slip. These are little clutches in the bath of oil. The fibre plates will wear and produce debris that is trapped in the oil.

Metal on metal parts wear so little parts of them get caught in the oil.

This is why the oil in there has a service life and needs changing.

Ayr_Rage

@raptor2004 here's little video for you.

https://www.youtube.com/watch?v=M1frtUn3TfE

Herzlos

Why do you keep doing this Darkmatter? We all know you don't have an M4, or a Carrera, and no-one cares. You're not impressing anyone by pretending to make a mess of looking after expensive cars.

Tucosalamanca

@raptor2004 this isn't normal. Have you tried talking to a friend?

I hope life improves for you.

boobyd

What happened to the Porsche?
Or the Yaris?

Stubod

It's a well known fact that BMW RWD cars do NOT have a rear axle. They use an alternative "capstan" gear system which means your deler is really trying it on. I strongly advise you confront the dealer with this and then find a better garage....

facade

Stubod said:

It's a well known fact that BMW RWD cars do NOT have a rear axle. They use an alternative "capstan" gear system which means your deler is really trying it on. I strongly advise you confront the dealer with this and then find a better garage....

Only partially correct I'm afraid, they don't have a conventional axle.

They use individual rubber drive belts from the variomatic unit to the wheels, so they don't need a differential, as the variomatic pulleys account for the variations in wheel speed.(This is the capstan drive you are referring to)

Usefully, if one belt breaks, you can carry on driving on the other (because there is no differential)