Bad Vibration - almost grinding noise

[t0mw]

I have a 94 Ranger with Mile Marker manual locking hubs. 4wd worked great the few days I used it last week.
Today when coming home from store, I had a lot of vibration & a noise coming from front. Kind of sounded like grinding but not quite the same. Sounded to be coming from right front. Hubs were locked in, but I was in 2wd at the time. Didnt start till I reached about 35 mph. Pulled over & I didnt see anything wrong, unlocked the hubs & relocked them again to see if one was not all the way in.
Continued home, going down hill, hit about 45 this time & a large bump in the road & it started again, same thing as before.
Took it to work, pulled both front wheels & hubs, looked for anything wrong, but didnt see anything, jusat that when I had the tires replaced last week, they didnt seat the o-ring properly & it was cut.
Put it all back together & started coming home, still with hubs locked. Vibration & noise started again.
Went back & pulled right front again, still didnt notice anything wrong, no wierd noises when turning by hand, and the hubs locked in.
Only thing I noticed was some play where the axle goes through the spindle. All U-joints had been replaced last year, as well as bearings.
Started home again & same thing at 35 mph. Tried putting in 4wd but no change. Got out & unlocked hubs & no noises or vibrations coming home.
What should I look at first ? Hubs, axle, U-joints or differential ?
Since there is play where the axle goes through the spindle, should I look at the spindle needle bearing ?
Oh, fluid was replaced in diff same time u-joints & seals & bearings were done, as I replaced a missing right front axle.

 

[Adrian87]

I am having a similar issue with my '88 Ranger. I don't have to hit a certain speed though, it's constant as long as the hubs are locked. If I figure something out, I'll let you know.

 

[kimcrwbr1]

As far as I know you do not want to have the hubs locked unless unless it is in 4wd. Have you tried putting it in 4wd and see what kind of noise it makes. What you are doing is freewheeling the driveshaft and U joints are designed to be under a load either way. Unlock the hubs if the noise goes away you gonna need to change a couple u-joints and more depending on the amount of damage. if you still have the noise it will require further inspection.

 

[dangerranger83]

The front hubs can be locked but all it will do is make the axle live and ready for shifting into 4wd plus it has everything spinning such as the diff and the front driveshaft when they dont need to be. It can kill your gas mileage a bit too.