Have you investigated the possibility of mud attached or debris around the drive shaft or is something now touching the driveshaft, i.e., stick, etc?

 

You are not alone. I think it relates to when the front wheels are engaged. Last time I asked this question several people had the same thing.

 

Every 900 (Ranger or RZR) that I have driven has that rumbling vibration when the front diff' engages. At first I thought it was the nature of the beast and just dealt with it because all was fine for over 3000 miles. Then the front diff' started leaking at the pinion seal and had a bunch of slop in it, so my dealer replaced it under warranty and now the vibration is almost completely gone. You can still tell when it engages, but FAR less than it was from the factory.

 

I have always had the front diff cage vibration but this is different and only occurs in 4 wheel drive under moderate to heavy accelleration. It is a vibration/grinding noise that I have never noticed before. I always keep my ranger washed and waxed and I remove the pro armour skid plate in the middle to clean everything. Just wandered if anyone else has ran into this.

 

Check your carrier bearing.

 

I will check the carrier bearing tonight. That kind of makes since to what I am feeling and hearing.

 

I had the same & had to have new u joints at 2900 miles. My buddies front u joint came out at 3200 miles

 

One of my U-joints was shot at around 3000 miles. The carrier was a little loose too, so I replaced all of them at the same time and upgraded the carrier to a pillow block unit with zerk fitting.

 

I only have 750 miles on mine but it has a 3 inch lift and 28 inch roctanes.