As the treatment is in so wait for few days to see if it works without the additional kharcha of new gear oil. I hope the sound will be gone for good.
The primary use of the oil treatment is with the engine oil but only if the engine is loosing/burning oil because of week rings or loose valve guides/seals, it helps reduce the blow, smoke and may help in stopping the oil reduction issue.
It makes the oil more viscous thus making it difficult to seep in the combustion chamber.