Front axel question

[kenfx4]

I have an 06 FX4 level 2 which is basicly stock drivetrain and ive been having alot of clunking which i thought was the transfercase. I took it to the dealership as i have 4 year warrenty, and they told me the noise was the front axels loading and releasing. Ive never had or heard of this problem on any other rangers and am just wondering if anyone has or knows what else it could be or what i can do because the dealer wont fix it because they say nothings wrong but with the noise and how much it jerks the truck im worried that its going to be serious. Any help would be greatly appreciated.

Thanks, Ken

still having problems, its slipping out of 4x4 when i pull away hard