D2[ 5J7882] Trans Oil

I recently drained and refilled the Trans.I refilled with 90w oil per suggestions in this forum.I have an old 1940 era Ford 9n wheel tractor that I am about to service also.The discussion forums for that tractor all warn against using modern gl-4 or gl-5 gear oils because they usually have additives [sulphur,etc] that are good for modern metals,but will hurt the "yellow metals" [brass/bronze] used in places in the old 9n machines.Are there "yellow metals" in the D2 trans that I should be concerned about?The 9n has "yellow metals" in the hydraulic system pump for the 3 point hitch .The hydraulic system in a 9n uses the trans oil.