2007 1500 Ram...61000....Changed wheel bearings last spring.....no problems.....all works well no noises ... used 4Hi the other day and notice ONLY when in 4wd...if feels like the brakes are on and something is making a noise ...not really a grinding noise but kinda sorts....flip it back to 2wd and noise goes away and drivetrain frees up...rolls freely and doesn't feel like your standing on the breaks.....cant feel anything when driving in 2wd front end seems tight..no sloppy ,loose or worn parts that I can find.....just wondering if this is a half shaft/cv joint problem or internal of the front differential...anyone had this problem or heard or it...thanks

 

Are your tires the same size front and rear?

 

Yes...tires are the same.....A little more info.....when in 4Hi....the rear wheels are locking up and skidding when going in a circle in gravel....and makes a whining noise...it has never done this...a fluids are full and fresh...had it on the rack and can see nothing at all wrong....how are the rear wheels locking up to match front wheel speed...at least that is what it seems like is happening....turn 4 hi off and it quits and it just like it should be...no noises...rear wheels are skipping or skidding...any ideas on why the rear tires are doing this.....cant find and wiring or anything at the rear end where this should be locking up electronically....but it is locking up somehow...

 

Something is binding up. As it only happens in 4wd, I would suspect something in the t-case, or front diff.