water in rear differential

Hi all, Iam new here and this is my first post so forgive me if I screw up. I noticed a growing humming sound somewhere under my 2000 f250. Thinking the noise was coming from my winter tires I went ahead and changed to my summer set. Same noise. I crawled around checking differential fluid, front diff fluid, u joints and such. I found water in my rear diff and think it has been there since last summers boating season. Probably put 6- 8 thousand miles on truck since. I then I pulled cover and drained old lube/water mix and cleaned out as as best I could. I could see no obvious damage, no metal flakes or wear on gears at least to my eyes. I replaced with synthetic gear lube. It still makes noise tho not as bad. Kinda sounds like tires with wear issues tho Iam not positive the rear end is causing the sound. Does anyone out there have any experience with this situation? Will my rear end last awhile? Should it be replaced? How big a hit dollar wise are we talking? Thanks

WELCOME ABOARD SDD Glad you found us.

Maybe there's no [visible] damage/wear to the ring & pinion, but you should get it checked for the proper clearance specs (lash). Also check the wheel bearings for wear.. due to any lack of proper lubrication ?

No idea what parts & labor is in Montana but if it's shot.. you might check out a used one ?

Joe

The carrier bearings may be pitted because of the water issue. That could be the noise. A teardown is the only way to check it out or run it till it makes more noise than you can stand.