One suggestion might be to drain the gear oil (take off the circular plastic filler port cover and tip the mower over). Then, after a day or two, tip it back on 4 wheels and put "00" grease in and see if it leaks. If not, you're set without messing with the seals. I got my grease on eBay and it was a Stenz brand. My own Snapper walk behind mowers (two of them) are happy with it.