I have noted a wierd noise (also feel in shifter) when I am traveling down the road in 6th gear. Kind of feels like the trans is burping. It feels real smooth then all of sudden the shifter vibration feels different and the regular humm will change just for a split second.

Do any of you guys have an idea what could be happening?

 

Checked the fluid level?
Didn't the 5600's have a problem with a nut inside backing itself off or something?

 

Fluid level is fine.

 

nuts on the nv 4500