Doesn't sound like your describing angles resulting from a lift as your problem, at first it sounded like the clutch wasn't properly engaging/dis-engaging, and I would have suspected adjustment or throw out bearing new or not, but, silver liquid from the tranny, unless you just hit a silver mine and plan on striking it rich, sounds like you've already determined your trans needs further inspection, I suspect bent forks, gears not aligning properly, if a driveline shop as you say, hasn't been able to pinpoint this, GET OUT OF THERE!! they don't know what they are doing, I don't care who you know there or have been going there for X amount of time, find a competent transmission shop, possibly even a 4x4 shop, ask questions about their familiarity with your driveline, I suspect you'll be looking for another trans or rebuilding that one. If your not the original owner of that Jeep or trans, you have no idea how it was used and abused, and with larger tires etc. off-roading etc., things wear out. Good luck, report back when have results.