I have been a JD owner for about 7 years. I bought a used L130, which had been abused some but reworked by the local JD dealer.
I have replaced blades, oil filters, etc., several times and 1 mower deck spindle, so far.
The crankcase seal has a periodic leak, mainly in the Winter, when tolerances shrink. The local JD dealer said it would be cheaper to just routinely replace any leaking oil because it would be quite expensive for them to replace the seal. So, I am waiting to make that decision and don't have to worry about it during mowing season, just snow pushing season.
I have a YouTube channel and have made several videos on maintenance and repairs, if interested private email me.
Looking forward to learning more from you experts and helping out, if I can?