Hey all I have a 97 2dr 4x4 Blazer. So this has happened a few times now (3 I think) all a few weeks apart, I recently topped off my front diff which I found almost a quart low. Basically when I am driving on the highway I hear a whining sound from the front left tire then when I get off the exit ramp and slow down the noise gets louder and lower like an airplane landing and doesnt stop until I stop, very oddly it has happened on the same stretch of highway each time after I have been driving at high speeds for about 15 minutes, now the first 2 times as soon as I came to a stop I would here a chunk or clack and I could drive fine, well this time it didnt stop and I tried going in reverse and there was no noise! I shut off my car put her in park and still the noise persisted loudest at low speeds, When I coast there is no resistance so I know the brakes are good and I assume the wheel bearing is good as it has no play and does not make noise in reverse So I thought I will try to make it to work in 4x4. I found no noise in 4x4 and so I switched back to 2HI and all was good, I think this has something to do with the front axle ot differential. Anyone have any advice? The 4x4 works fine. Thanks.

 

Couldn't be more direct and to the point:
4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO

 

It isnt a clicking at all could this still be the problem? I have read that thread a couple times and it just slipped my mine! Thanks man! by the way whats your name? Im Dillon... Also I have a np233 is that the same as the nv233 and the np233c ( The C just indicates Chevy correct?)

And I think I have a faulty transfer case input seal but I drain My t-case everyother day to prevent problems (from the fill plug not the drain plug) and was wondering if atf in the vent line cold cause this? Does the fluid only go into the lines from the t-case switch with the 3 lines on it or the single hose hooked up on the back of the t-case that one goes to what appears to be the shift linkage on the side of the tranny. So I figures as ling as i dont switch into 4x4 the t-case switch will stay closed thus not allowing atf to get into the lines if the t-case is over filled... is this true or is that other single line in the back where the atf get into the hvac system? Thanks sooo much