running the amsoil severe duty gear oil as I do tow a trailer occasionally and ride 2 up
the one quart will probably Still last another several years at the rate it gets changed
Severe Gear 75W-90 Product Code: SVGQT-EA Ordering Instructions
Engineered for high-demand applications, including trailer towing, heavy hauling, 4X4 off-road driving, commercial use and racing. Protects gears and bearings from scoring and wear. Excellent cold-flow properties. Outperforms all conventional gear oils. Recommended for all types of vehicles.
It was 12 bucks in 2004 when I bought it
link click here
http://www.amsoil.com/a/synthetic-gear-oil