Transfer case oil change procedure

[Clark Kent]

I certainly hope it isnt as cosmic as a drain/ refill of the DSG fluid in my Audi. That requires a fairly involved procedure, where a scan tool has to be hooked up and the transmission needs to be within a certain temperature range to accurately service and fill it. Too little or too much fluid is catastrophic.

The ZF 8HP auto is very similar.

View: https://youtu.be/kXKhZievmSI?feature=shared

 

[HereinDaRockies]

lol German engineering… I laugh while mentally calculating the half-life of all the plastic components in the IG’s b58. pretty sure I saw that the IG’s hvac unit was subcontracted to a German firm.

 

[Clark Kent]

lol German engineering… I laugh while mentally calculating the half-life of all the plastic components in the IG’s b58. pretty sure I saw that the IG’s hvac unit was subcontracted to a German firm.

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[NQ94]

The ZF 8HP auto is very similar.

View: https://youtu.be/kXKhZievmSI?feature=shared

Nearly every modern torque converter auto has a similar procedure for changing the oil. Even the the dealers with the correct tools get it wrong occasionally.

 

[Tazzieman]

lol German engineering… I laugh while mentally calculating the half-life of all the plastic components in the IG’s b58. pretty sure I saw that the IG’s hvac unit was subcontracted to a German firm.

Are you speculating , or do you know about modern plastics (derived from Ineos chemicals )?
Plastics made in 2025 are not the same as those made in the 70s/80s (though plastic parts in my 70s/80s Porsches are still absolutely fine)

 

[HereinDaRockies]

Are you speculating , or do you know about modern plastics (derived from Ineos chemicals )?
Plastics made in 2025 are not the same as those made in the 70s/80s (though plastic parts in my 70s/80s Porsches are still absolutely fine)

BMW engine plastics failing is a well known weak point.

 

[Tazzieman]

BMW engine plastics failing is a well known weak point.

I'll just quote a random guy off a BMW forum
"Show me examples where plastics are problematic…… I can tell you that the N55 has two plastic items that are problematic. The turbo intel pipe and the charge pipe.

Most of the other plastics in the N55/B58 as long as the car is cared for and the coolant is replaced at the appropriate intervals, there are no issues with the plastic items in the cooling system.

Valve cover leaking is not due to the material of the cover, but the actual gasket. Gaskets have never lasted forever, before plastics. Just like some claim plastic warps so does metals. Dissimilar metals expand at different rates and plastic is possibly the best metarial to have.

I can tell none of you complaining about plastics have a clue about material science or even come close to having a degree in the field of engineering"

 

[Greasemonkey]

So talked to the tech in San Antonio and apparently the max fill on the diffs is supposed to be a couple MM’s below the top of the fill hole. So you aren’t supposed to fill it all the way up or it is over filled.

Today I changed the oil in the front differential after 18500 km. After opening the drain plug, 2,180 liters came out, which I exchanged for the same amount of Fuchs Titan Supergear 80W-90. With this amount, the oil level in the diff was. approx. 1 cm below the inspection opening. Tomorrow I will find out how oil is in the rear Diff. For 20 liters Diff oil I paid 85,44 Euros. That's less than 10 Euros for an Diff Oil change.

 

[HereinDaRockies]

Today I changed the oil in the front differential after 18500 km. After opening the drain plug, 2,180 liters came out, which I exchanged for the same amount of Fuchs Titan Supergear 80W-90. With this amount, the oil level in the diff was. approx. 1 cm below the inspection opening. Tomorrow I will find out how oil is in the rear Diff. For 20 liters Diff oil I paid 85,44 Euros. That's less than 10 Euros for an Diff Oil change.

How did you measure a delta of 1cm between oil level and fill hole?

 

[ORSO]

What tightening torque is prescribed for differential caps?

 

[Greasemonkey]

What tightening torque is prescribed for differential caps?

31 Nm

 

[Greasemonkey]

How did you measure a delta of 1cm between oil level and fill hole?

With a cable tie. However, this method is very inaccurate because the cable tie cannot be inserted into the housing at a right angle. That's why, when I filled it, I initially stuck to the amount that had previously flowed out.

 

[HelgeL]

Have you changed the O Ring as well? And if yes, where did you get them?

 

[Greasemonkey]

Have you changed the O Ring as well? And if yes, where did you get them?

No, this is a special O-Ring. Much stiffer than the usual black ones. Maybe a Viton ring. I think for now it is ok.

 

[HereinDaRockies]

With a cable tie. However, this method is very inaccurate because the cable tie cannot be inserted into the housing at a right angle. That's why, when I filled it, I initially stuck to the amount that had previously flowed out.

But how much difference can 1cm make ? Not much I am assuming. It’s not a high precision mechanism

 

[Greasemonkey]

But how much difference can 1cm make ? Not much I am assuming. It’s not a high precision mechanism

Today I changed the rear differential oil. I made myself a special tool to measure the oil level in the Diff. (see picture) It was 23 mm!! under the bottom edge of the filler plug. I drained around 2.2 liters, which corresponds to the information in the table. I also refilled this amount. I don't know why the oil isn't topped up to the overflow.

 

[HereinDaRockies]

Today I changed the rear differential oil. I made myself a special tool to measure the oil level in the Diff. (see picture) It was 23 mm!! under the bottom edge of the filler plug. I drained around 2.2 liters, which corresponds to the information in the table. I also refilled this amount. I don't know why the oil isn't topped up to the overflow.

Oh 23mm. But you previously said it was only a delta of 1cm?

 

[Greasemonkey]

True, but I also said that this first measurement was not exact. But actually this measurement doesn't matter at all. If 2.1 liters come out and 2.1 liters have to be refilled according to the table, what else do you want to measure?
I'm more interested in the reason for such a low oil level. Since I can't answer that, I sent an email to my dealer today and asked him about it. If I get an answer, I'll share it.