I have an 8-yr old model 125 lawn tractor and I change the oil/filter regularly, but something is always bugging me. When I ask at the JD dealers and even when I purchase the service kit, I am told to use 1 qt of oil. But, if I use 1 qt and check the dipstick, it tells me I need to add oil, may be another 3/4 of a quart. I checked the manual but didn't find this information (maybe I missed it each time). How much oil does the 125 take?