I have been having problems with my 4 wheel drive...The problem is a pop that i hear and feel while driving down the road in 4 wheel drive. I've heard a couple things that it could be. I've heard that the ujoint is bad...I replaced it, I thought it might be the front diff spider gears, already checked them! I've dialed it down to the transfer case but I don't where to start looking on the transfer case. I'm pretty sure it's not the motor or the drive chain. What else could it be?

 

what universals did u replace the drive shafts or the 3 in the front axel?
how did the ring and pinion look?
is it electric engage or manual engage t-case?
and manual or auto hubs?
does the pop only happen once or continualy?
does it happen only when driving?
does it only do it in 4wd or 2wd?
if just 4wd does it happen in hi or low or both?

if all checks out id make sure the t-case is goin all the way in gear.

 

I just replaced the left ujoint because that's the one that looked like it could have been bad. The ring and pinion looked fine. It is electric engage. I have manual hubs, those were the first thing I replaced to try to fix the problem. It only does it in 4 wheel drive, it does it both driving down the road and when on a lift, although it takes much longer for it to do on a lift. The pop happens continually, the harder the surface the more frequent. I haven't tested the 4lo just 4hi.

 

I don't know whether the F150's have a CV joint on the front shaft or not, but if they do, check that for sure. Grab the driveshaft at the end closest to the transfer case, and try to move it up and down, left and right...if you get some play, even just a small amount, replace that u joint. Do the same for the end closest to the front diff. Make sure all your u joint straps are tight. This might be silly, but check the fluid level in your transfer case.

 

if its doing it on the lift just pop out ur front drive shaft and if it still does it its in the t-case if not its in the axels bearing

fishsniper later f150s 97+ had cvs but b4 had ttb with 3 universals

 

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Thanks all for your input. I did end up zeroing in on the tcase and just ended up replacing it. Everything is fixed now, so thanks for all the help

 

This may be a day late and a dollar short, not to mention what I would think to be some level of common sense, but why are you on hard pack in 4x? If the ground below you isn't giving and allowing a slip in traction, then I wouldn't engage the transfer at all. Perhaps leaving the axles locked at various times for any number of reasons is sound, but not running in 4x unless you are on varied terrain or poor weather. This action alone would be enough to wear and tear on the drive train. Leaving any vehicle in 4x, that is not designed to be all wheel drive, will cause undue wear and tear out one of the drive line components. In this case, the transfer seems to have been the weak link, although I find that surprising. I agree with an above comment that perhaps a bearing or U-joint would have been the culprit, unless some other neglect has affected the transfer case itself.
In any event, I hope you have found the problem, resolved it, and will many happy miles.