250sx noise question

[sj13]

I think I am hearing a little gear noise in third at 3/4 throttle and above... Sounds like somethings got a slight rattle. It shifts great and runs strong. Could it possibly be the u-joint in the drive shaft?

[atc vending guy]

I think I am hearing a little gear noise in third at 3/4 throttle and above... Sounds like somethings got a slight rattle. It shifts great and runs strong. Could it possibly be the u-joint in the drive shaft?

my buddy just had the same problem.we checked it out and wasnt the joint,however he didnt want to pull the diff and we went out riding and it locked up on the trail.got home pulled the diff and the bearings jammed the diff gear.only was noisy in 3rd+ gears.just a thought,and it is easy to check.

[sj13]

is that an easy fix? I just changed the rear end fluid and found a few metal shavings....