I have not seen Novaks site for a good long time. It is all new and pretty cool. I did find more specific T98 info. Plus this on oil...

When filling your T98 with gear oil, we recommend that you select a conventional mineral oil or a para-synthetic in lieu of a full synthetic oil. Properly assembled manual gearboxes do not have the thermal strains seen by combustion engines or hypoid gears. Synthetic fluid in these gearboxes, while not harmful, is probably an economic waste.

Hypoid gear oil is sulphurized higher than transmission oil and can be mildly corrosive to the non-ferrous alloys used for synchros, bushings and thrust washers in these transmissions.

An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment.

That was from this page.

http://www.novak-adapt.com/knowledge...ons/manual/t98

So it would be a wash it sounds like. And since I bought the conversion roller bearings for the Jeep J truck input swap into the T-98 already, I will stay the course. Thanks Gonz for the link to Novak. !!