I've got a 04 2500 4wd dmax quad cab, that when gong down steep canyons (especially with a trailer behind) the steering fells "grabby" like the belt gets tight, then loose, then tight again. My son noticed it on a trip yesterday also.
Anyone else have this happen? Any ideas? Thx!

 

That sounds strange, I haven't noticed mine doing that.

 

Yeah, mine make a little noise and feels almost like it's low on fluid, this is unloaded...