About a year ago, on some tractor forum somewhere, I posted about using Lucas Hub Oil in the 4WD front-end of a tractor with leaking seals .
Its a long story about that little tractor. After I bought it, I found that the entire front end had been filled with grease -- that's a whole nother story. It was still leaking. The seals were not only expensive, but darn hard to replace. After I did the first one, I was in no humor to do the other side. I also found other major leaks after I got all the grease out, replaced the first seal, and put in standard 90-140W oil.
In my quest for an answer, I found out about Lucas Hub Oil. It is meant for trailers (like in semi-trailers) with really leaky seals. I was told that the Hub Oil is so sticky that even if it all runs out, enough stays on the gears and bearings to keep things lubricated for a very long time.
The stuff has a look and consistency of warm honey, but it is a lot stickier. It actually pours and squirts fairly well. It smells like the fumes you might expect from the Gates of Haides.
Anyway, I filled the whole front-end with the stuff. The side without the replaced seal weeped a little bit when I first filled it. It wept again one time during some fairly hot weather when I was doing some grading on a steep hillside. After that, it never leaked or wept again. Every once in a while I'd check the levels to make sure it hadn't somehow snuck out. It didn't.
I was concerned about winter use, but that didn't seem to be a problem at all. I used the tractor regularly last winter in 10 to 20 degree F weather without any issues. I put about a 100 hours on that tractor after doing this work. I sold it not too long ago, but told the new owner about what I did, and I gave him a quart of the Hub Oil.
I found the Hub Oil at a parts store that specialized in repair parts and tools for tractor trailers and other big trucks. It was about $7 per quart.
Good Luck,
Knute