Rumbling noise and vibration at 75 mph

[racerken]

I have 60k miles on the pathfinder with clean fluids: front/transfer/trans/rear. The original tires were BF Goodrich AT's. At 75mph, there is rumbling in 4w auto and gets louder when set to 2wd. I thought it was the tires so I swapped them out last week for Bridgestone Revo 2's. I also applied rubber sheet in the interior before blaming the tires. The rumbling remains...

Any ideas on the cause? I can't tell if it's coming from the rear or from the transmission/transfer case.

I thinking that the likely candidate would be a drive shaft missing a weight so I'm planning on taking the car to get the driveshaft balanced.

Any clues out there?

Thanks,

Ken

[miamiheat3332]

im 95% sure one of the weights came off the driveshaft, i had this issue about 10 months ago, and i took it to get balanced, works perfect now. Also look up directions on how to take it out, and mark the points with a marker so when you slip it back in the transmission section and the axle it goes in the way it came out.

[racerken]

Thanks, I'm going to take it out this week.
BTW, who balances shafts?