Disco 2 How do you judge D2 auto gearbox leaking from output shaft

I got oil leak from the input shaft of transfer box, I degreased and dried the t-box, I found yellow drips from the seam between g-box and t-box after a while of drive and didn't see any pink. I drove to a garage for quote, they told me it is also leaking at g-box output which drives t-box. They didn't give me any evidence, but said he will show me once t-box is removed. Any idea to know how leaking happens at g-box output seal.

Well with tfer box out of the way the geabox output seal is very easy to replace, literally a few minutes work, so it would be mad to not change all the seals whislt you are in there.
If same as the D1 there is a drive adaptor between the gearboxes.