Might be slop in the shift cable, shift fork or bearings in the trans. The shift cones are on a spiral spline, as soon as the cones start to drag, it grabs and pulls it into gear
(foreward or reverse). You might try idling the engine
down more before shifting.
Another thing to look out for, the shift fork is in a depression on the top or the trans, under the water
pump on a MD11. If water gets on it, it has nowhere to go but into the trans and make a rusty mess out of things. Speaking from experience.