I changed the transmission oil on my B7000 for the first time since i've owned it. To drain I removed three drain plugs & let out all the old stuff. I removed & cleaned the filter and then put new oil back in. It is supposed to take 11.5 L to fill up but I only got something like 10L in before the dipstick showed full. I ran the tractor for a while and worked the hydraulics to get the oil everywhere it should be and everything ran fine but would not take anymore oil. My two questions are: why couldn't i get he specified amount of oil in. Also, is it normal that the oil would be really foamy after running for ten mins. I used gear lube 80W-90.