Howdy KeveW
Your tractor 83J1594 would take cat P/N 4W4840 plus you will want gasket/seal P/N 2M8691 as well.
Billy
NAPA should be able to interchange the Cat number with theirs. I went to town yesterday to get filters and oil for an oil change in my Cat 12E grader. .come to find out it's the same number for the filter in the D4 U dozer, NAPA 1161 as I recall. I wouldn't be surprised if yours turns out to be the same. . .