I have a 79 f-150 4x4 w/ the np 205 transfer case that is making a noise when you go above 40 m.p.h. and are at lite trottle or just starting to coast. It sounds like a chatter/grinding noise. I just had the slip joint of the front driveshaft rebuilt (had some play). Is there a bearing behind the yoke on the transfer case that may have gone bad as the front drive shaft was flopping around? At speed or as you under a load I don't hear anything or at a coast once your speed begins to slow> THANKS FOR ANY HELP/IDEA'S