Here is my take on it..If your doing alot of rockcrawling and have a stock thinkness driveshaft ,,then the slip yolk should go towards the diff,,,reason is it gives you a few mor inces of space to beat on so that the tube does not get dented..the youlk can take a good beating...If your just running regular trails then run the slip atthe top near t-case..i think there it takes less abuse from the weather,mud and grime...but other then that it really don't matter..