Yes used to go to a few pay and play sites, always went for the deep water! learnt that only way to make sure was to strip and regrease after every day out.
tAxle oil in the wheel beaings is quite normal, not correct but not unusual, some people remove the axle seal ro allow the oil into the hubs as the grease only set up is a bit ****.
So warning light is on with ign on but engine not running?
Then when you start the engine the warning light stays on?
Sure the warning light wire is on the correct terminal? pic of the back of the alt might help someone pinpoint your issue.
You sure it was smoke free on start up before the road trip?
I ask as I have never actually looked at my tailpipe when starting.
Though I have seen a few 200 gob out black smoke on start up over the years.
200 are a dirty engine, 300 less so.