Change oil in rear differential

[rbhelle]

2011 Superb, 4x4 haldex 4, DSG DQ 250 gearbox MTZ, engine CFFB.

Rear diff oil: Manufacturers specs are G052 145 (75W-85 API GL-5). BUT, this oil is primarily choosed by VAG since it gives a bit better mpg due to is viscosity (thinner). For endurance, I use G052 911 (wich is 75W-90 API GL-5). It is marginally thicker, but gives more lubrication. 

 

Tools needed:

• 5mm HEX pipe
• ratchet
• bucket
• some kind of oil pump etc.

Get the car up, should e level when raised. Identify the fill and drain plug on you axle. Beware, do not mix up the haldex fill and drain plug. I would say that it is not easily mixed up, but have heard about some garages that actually drained the haldex oil instead...

Undo the fill plug with hex key before you undo the drain plug. It should drain approx 0,8-0,9 ltr of axle oil.

Torque the drain plug to 15NM. Manual says to replace it, but I didn`t replace it, it worked fine.

Use a pump with a 6mm hose to fill through the fill hole until it drips out in a steady flow. Close and torque to 15NM. Job done.

 

Picture layout:

1. Drain plug haldex oil (do NOT loosen)
2. Fill plug haldex oil (do NOT loosen)
3. Drain plug axle oil rear differential (5mm hex)
4. Fill plug axle oil rear differential (5mm hex)

[J.R.]

I bet the oil that you drained out was as clean as the new stuff you replaced it with.

 

If that happens when you (think you) drain the Haldex it is a massive flag telling you that you have drained the diff by mistake.

 

Dont ask me how I know

[rbhelle]

24 minutes ago, J.R. said:

I bet the oil that you drained out was as clean as the new stuff you replaced it with.

 

If that happens when you (think you) drain the Haldex it is a massive flag telling you that you have drained the diff by mistake.

 

Dont ask me how I know

No mate, oil was not as good as new oil. Luckily, I did not drain the haldex, but the rear diff axl oil 😀 But, yeah, have heard abouth them draining the wrong one 😅

[Bap33]

@rbhelle What was the mileage of your Superb, when you changed the rear differential oil? 
 

I should change my Haldex oil within one year, I just ask myself if I change the rear differential at the same time🤔…

Currently 116000km on the clock.

[rbhelle]

2 hours ago, Bap33 said:

@rbhelle What was the mileage of your Superb, when you changed the rear differential oil? 
 

I should change my Haldex oil within one year, I just ask myself if I change the rear differential at the same time🤔…

Currently 116000km on the clock.

Rear diff had approx 202 000km. So way past what it should. On the other hand, VW/Skoda/Audi claims that rear/front diff oil is "filled for life"....Anyway, do replace it and your car will have a much more pleasant life overall 🙂

[J.R.]

It wont make any difference at all unless you have stupidly run the diff dry like I did by mixing up the Haldex and differential drain plugs, in which case the diff will need all the help it can get and I am soon changing mine again.

 

VAG are correct, the rear diff has such an easy life, is so well built and the modern oils so good that it never needs changing, and I can attest to this as when I mistakenly drained the diff oil that had done 79K miles with abusive fleet drivers (the clutch bore witness to that) the oil that came out was indistinguishable from new oil, that should have rung alarm bells for me but didn't.

[J.R.]

An analogy would be to compare the rear diff with the front diff on a FWD car which does not even use differential oil and shares the gearbox oil, that diff transmits 100% of the drive torque 100% of the time that the vehicle is operated and never needs the oil changing although given what it does it would not be a bad idea.

 

The rear diff transmits 50% of the drive torque maybe 10% of the time so being generous endures say 5% of what the front one does and it has its own independant correct grade oil not being sheared and heated by transmission gearing.