When I got my Disco everything in the steering leaked that could. Lines, pump and gearbox. I only paid $300 for my disco so I replaced all of that. Total cost for all the lines, pump and gearbox was around $700-750. The gearbox being the biggest price tag. It was easy to replace and in hindsight I wish I had tried rebuilding it first. If I did it right it would have saved me about $450... I got a remaned gearbox off of Ebay I think and it was still pricey and there was a core charge. I filled it with ATF and works great with no leaks more than a year later.