2qts on a change in a stock trans builds up to much pressure thus the oil doesnt flow as well. The manual states 1.6qts. I buy 3 quarts Motorex fully synthetic 30wt and have enough for 2 oil changes. This oil is good for wet chutches and will not soak in. I think its the best trans oil money can buy.
http://www.ktm-parts.com/mm5/merchant.mvc?...t_Code=36030002
Motorex Synthetic Gear Oil 10w30 1-Liter
Synthetic blend transmission gear fluid for use in all 2-stroke engines with a wet-clutch. Can also be used in 4-stroke engines with a separate transmission and wet clutch. Use wherever 75wt, 80wt, or 85wt Gear Oil for 2-stroke motorcycles is recommended.
SAE 10w/30 (75wt/80wt), API GL-5