Steady popping noise in 4x4

[sgg93]

I have a 1995 F350 4x4. Manual hubs. The front end work was done mostly by a mechanic, and I don't trust any mechanic. The front end has new tie rods, new ball joints, new U-joints on the spindles, and new wheel bearings (I did those). When the truck is in 2wd it is silent. When i put the transfer case in 4x4 and leave the hubs unlocked it is silent. If the truck is in 2wd and the hubs are locked, there is a popping nosie that eventually becomes a squeaking noise (after 5-10 miles). If the transfer case is in 4x4 and the hubs are locked, there is a loud popping/knocking noise that is louder with more throttle (but also occurs during deceleration) and in turns. I suspected locking hubs were causing my problems, so I switched them around. The noise seems to be unchanged. I'm wondering if the U-joint going into the differential is a problem, or if it is my passenger side spindle u-joint, or if I do indeed have hub problems. 4x4 works OK, but the popping noise gets very annoying, and i'm a little concerned that I'm making a problem worse by letting it continue. Any ideas?

[garyeco]

I had a problem like that once and it turned out to be the constant velocidy U-joint. The one from the transfer case to the front end.Try to pry a screwdriver or something in it to see if it wiggles at all,especially the big end. The spring assembly in it will go bad due to lack of grease{it can be a ***** to get all the zerks].Anyway I hope you find your problem,goodluck!

[ryandamo]

might be the bearing in the spindle that centers the axle shaft or perhaps one of you hubs are stripped

[sgg93]

are stripped hubs fairly common? I first noticed the problem when I was sunk down in the mud, but then agian that was the first time I'd really used 4x4. This was after U-joints, btw.

[ryandamo]

its probably not too common, one side didn't lock up properly or something and ground the teeth a little bit, you would notice taking it off right away though.

take them out and click them open and shut and see if both sides are engaging properly, also check that bearing in the spindle.

Also keep in mind that if you put it in 4x4 with hubs unlocked and its not making the noise, that doesnt rule out all of the parts that are moving. They dont have a load on them which could prevent them from making the noise. If you had your differential in the mud, i would also drain it each and every time you submerge it. Its better to change it often with cheap fluid if your doing that kind of stuff. Also try shooting grease into all of the u joints

[sgg93]

It decidedly pops louder when it's under a heavy load. The differential is full of clean oil, and switching the hubs didn't change the noise. This leads me to believe that the u-joint going into the front axle is bad, and it isn't greaseable. I'll grease the ones on the spindles, and go ahead and change the one going into the pinion.

[ryandamo]

also jack up front of truck, turn the wheel all the way to left and try spinning tire to see if one of the u joints on the axle shafts went bad, even though you replaced them

[sgg93]

Ended up being the ballsocket in the double cardan joint by the transfer case. A $100 job that took a little over an hour.