I have the exact same vehicle and issue, though mine happens at higher rpms 2K and 60mph + as well...looks like no one replied to your post. Have you found out in the meantime from another source? I'm taking mine in on Monday

 

I took mine in and they did a courtesy check up on it and said they couldn't find anything wrong with it. If they find out what your issue is, please post here and i'll take it back in and tell them where to look specifically

 

Do you guys ever recall going over something and high centering it on your drive shaft?
I have seen someone do this (not offroading) but just drove over something and it bent there shaft a bit.

 

could be wheel balance, a motor mount, alignment(less likely), etc..

seem more from wheel of engine??

 

It seems like either transmission or rear dif. it seems like the noise comes from under me or behind me.

 

i know you said "drunk bumps". but does it sound semi metallic (heat shields on exhaust pipes) or more like a wobble (wheel balance, axle balance, uv joints, possible but doubtful trani mount)

 

i have the same grinding noise lasting for few seconds . the noise is occuring more frequently, i hope there is a recall for this cause i do not want to spend big bucks on this issue. It's coming from my rears like going over the rough edges of the highway( patches to wake you).

 

I have the same issue with a 2005 Xterra SE 4x4. Feels like rumble strips and only lasts a few seconds. I replaced the rear driveshaft u-Joint this weekend and it did not fix the problem!

 

Update on vibration-repairs

Since I started this particular thread I'll update the repairs I've had done to fix this problem.

Rebuilt transmission (due to failed radiator/aux tranny cooler and strawberry milkshake of death)
Replaced U-Joint
Replaced Rear Drive line

None of these have solved the problem. I'm done putting money into this vehicle for now.

 

same issue with a X02 the mechanic says that the tires are causing this , the mechanic already made the wheel balance twice and nothing happens, also this problem happen when I brake but is a little vibration.

 

same issue Im having with 2k X, replaced distributor, cap and rotor, sparkplugs, wires, fuel filter, fuel pump, MAF. new drive belts. only thing that is not replaced is the timing belt. it has slight vibration and light ruble. my rpm is constant at 600-700ish, needle does NOT move at all, but you will feel that it kinda fluctuate just a tad bit. im running out of things to check and replace. could it be BAD injectors? maybe seafoam will cure the light vibration? it does it more if the car is in N and P, on D, it will but if you accelrate it goes away.

 

Here's the fix!!!!!!!

There is an inherent fault with the transmission cooling lines. The transmission sends lubricant up to the radiator where it’s cooled and then returns back to the transmission. The problem is at the radiator where a failure in the radiator causes coolant to be mixed into the transmission coolant lines. This causes the transmission to "shimmy" as it isn’t being properly lubricated anymore. Because of this Nissan has extended many owners radiator/transmission warranties out to 80,000 miles. Nissan is replacing my transmission, radiator, and lines for free! I'm very lucky as I have 72,600 miles on my truck.