Gear oil for trans and rearends

[Toolguy]

(12-10-2016 )Johnboy Wrote:  Honestly the not changing the oil is the biggest reason I see rearends go for some reason people seem to think the synthetic oil doesn't need to be changed.
Personally I use the synthetic with half a gallon of lucas in the rearends and 50w in the transmission. I have thought about changing to conventional 80w 90 after an internal cooler cracked in a trans and filled it with antifreeze I drained and filled it with 80w90 to get it home.
That was the best it had ever shifted literally clicked in and out of gear where it had always rumbled a little bit. I was just curious if any of you had tried it thanks for the reply.

Granted this is a was a ways back, but why would you put Lucas in the rear gears? Lucas has no additives and gear oil/lube does?