I only hear a grinding noise on my 400ex when it is in gear and driving can push it without it in gear and there is o noise. Any info on what it could be would be great.

 

I would check the axle bearings. They go out frequently on the 400.

 

Do you have to buy the whole axle or just the bearings I took it apart and found the bearings are bad in the axle but every where I look they just sell the whole assembly

 

Time to invest in a service manual!

 

i would buy the whole bearing carrier. $90-$160 on ebay. modquad, and lonestar are makers of good billet carriers.

 

I have found the bearings at industrial bearing stores. We have a Kaman and an Allied Bearing in town. I am sure you can look up something like that locally.

You can go the more expensive, but way better route. That is buying one of the billet carriers on ebay.