I do not know if it can be used safely in a transmission ("in a way that is not likely to cause or lead to harm or injury" to the transmission parts).

If this link works, it gives results/answers for your question)?

It seems that desperate people do desperate things?

If someone does it to a transmission they intend to sell/swap, it would be dishonest.

However, if it works for the owner, "so be it"?