Vibration in drivetrain

[meanjean]

Ok here is a stumper. I have a 2000 F250 CC SB 4x4. Sometimes when I hit a bump I get a grinding noise with a vibration. It seems like its coming from the transfercase. When I hit another bump or dip in the road is will stop. If I come to a stop it will go away. Or if I put the T-case in 4x4 is goes away. Local mechanic thought it may be carrier bearings and U-joints. The truck had 71k so I replaced them, figured they were due. Still the noise is there. It has to be the T-case. Also had the wheel bearings checked just to rule them out. I really belive its something in the T-case but Im not ASE certified so what do I know. Anyone have a problem like this in their SD? Or any T-case problems? I dont want to spend more money on something that isnt broken and T-cases cant be cheap to rebuild.
Thanks.

[Fis Teck]

There is a bearing in the spindels on the front axle that the axle sets in. If it's bad it can do what yours is doing.

[meanjean]

A mechanic found just that. The bearing is shot. He also said the drivers side hub assembly is rough. Recomend replacing both sides. With only 71k and at a cost of $1000 that seems like alot. What have you guys found with the the front wheel beaings? How often have you seen them last? I have bone stock set up. Kinda frusterating that they got ya by the balls

[99Smokin73Stroker]

I once read in an offroad magazine that the 99 up super dutys were notorious for wheel bearing failures in their early lives so it's not a surprise to me!

[Fis Teck]

Water is what I have seen that takes them out. It gets past the seal and rusts them out. Not knowing what you use your truck for or how or how it was used if you got used, it's hard to what the cause is. Poor disign by the axle maker because I have seen this same problem on GM and Dodge, too. Plus you have to pull the spindel to get at the bearing. Thats not a mantanice thing, you would think.

[meanjean]

If a guy could come up with an affodable way to replace the design he could make a ton of money. I know there is a "convertion" but at 3k thats way to much. For the price you would think you could swap a front axle from an older F250/350. They dont have the same bearing design. Any one here replaced the hub units yet? How many miles did you get? Mine made it a whole 71k. I was told the average was around 100k?