Is there any service access to change the oil in the transfer case (technology holes to drain and fill up the oil) or it need to be taken away from the car and split in 2?
What does the service manual say and how it looks?

What oil will be needed and how many litres?

Would you recommend any oil additions, like liquid sealants (Liqui Moly has one for the gearbox)?

 

>Is there any service access to change the oil in the transfer case

Don't know, but 15 months ago I had the dealer do a complete awd diff service where they did a drain/refill on the front & back diffs and the transfer case.
It cost $299 service and $100 for fluid.
That was with a dealer near Boston MA.

Based on the price I'd have to say that it must have been pretty simple service ...
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Current Hers: '13 Lexus ES350
Current Mine: '15 Jaguar XF (X250) Portfolio AWD
Jaguar - making mechanics out of customers since 1935

 

I found the answer in the meantime.
Service access for oil service was described here https://www.jaguarforums.com/forum/x...cement-237593/

It looks pretty easy, indeed.
I've asked my Jaguar shop (not the dealership) about the oil change in diffs and transfer case and they answered - that it's lifetime oil no service needed.
However, the transfer case in my jag has a very tiny leak. Their estimation to solve it was ca. 1200$

 

>I've asked my Jaguar shop (not the dealership) about the oil change in diffs and transfer case and they answered - that it's lifetime oil no service
Check the factory service guide, mine listed it at 90K mi/6yrs or sump'thn like that.
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