This is my first post so apologies if I’ve done this incorrectly.
I am about to do a full service and I have seen posts on here about the transfer box, regarding a double flush, please can I ask what fluid you use to flush the box out before installing the new oil?
Thanks.

The double-flush is just a 2nd oil change. However it is only done in conjunction with a clutch re-calibration when there's been an issue with the clutch not releasing properly, with a common sympton of scrubbing tyres when cornerning slowly.

Thanks for the information. I am experiencing these symptoms and this is why I thought I would carry out a full oil change of both diffs and the transfer box. Do you know the full procedure for replacing the oil/flushing of the transfer box or where I could find it?

I expect that the 2nd oil change wouldn't be necessary but if changing it a second time then run the engine to allow the remaining old oil to mix with the new oil then change it again. There isn''t a special procedure. Recalibrate after your final oil change.

Thanks, I’ll give that a try and see if things improve.

Make sure you drive the vehicle after the first transfer box flush to mix the oil and new oil together. Then drain again.

Procedure:
- drive vehicle to warm oil
- remove fill plug first
- remove drain plug and crush washer
- let warm oil drain
- replace fill plug with new crush washer
- fill transfer case with fresh oil using correct spec
- replace fill plug

- drive vehicle to warm and mix oil (I did this over several hundred km and a week)
- cycle from high to low and drive
- cycle from low to high and drive

- drive vehicle to warm oil
- remove fill plug first
- remove drain plug and crush washer
- let warm oil drain
- replace fill plug with new crush washer
- fill transfer case with fresh oil using correct spec
- replace fill plug
- use GAP IID Tool to recalibrate the transfer case


I used 3 litres total of Royal Purple Syncromax for my twin speed transfer case. I don’t know the spec if you have a single speed transfer box.
https://www.royalpurple.com/product/synchr...ion-fluid/ Dan. 🇨🇦 2013 L405 5.0 SCV8

Thanks, very informative.

I do have a twin speed box, I won’t be able to get the oil you recommended due to the cost of importing it into Spain. I am using Ravenol DTF-1, TF0870. I have had to ship that in from Germany but it’s still cheaper than going to the main dealership.

The slight judder only happens occasionally so hopefully this will resolve the problem, I just need to order some more oil now.

You are welcome. I could not get Ravenol. It’s good oil. Pentosin is great too if you can find that. Dan. 🇨🇦 2013 L405 5.0 SCV8

Thanks for your help.

I finally got round to changing all the oils in the diffs and transfer box including the flush on the transfer box. All seems to be fine now, no scrubbing of tyres at low speed anymore 👍👍
Thanks for all your help.