Bad Gear/trans/diff Noise under left bottom HELP...

[pepeancon]

I have replaced the whole front Differential for my AWD 98 explorer V8, about 4 days ago, the other differential came from another V8 AWD Explorer (same year), I checked the Ratio and counted all teeth just to make sure is was exactly the same, and it was same exact unit, the car was driving fine for 2 days and yesterday morning while I was driving I felt something like a gear noise coming directly from the left tired, the sound was like tapping metal with metal everything the wheel turns, then the noise was gone completely, after 1/2 hour driving in normal conditions the noise came back again this time louder, and to the point that I could not go far, instantly I had to tow the car to my place, I lift the whole car and ran it and the noise was gone, there is nothing coming from the differential, all shaft are fine, the noise comes front the button left side when the car is on the road with all its weight, so I started to pull everything apart, thinking It was the bearings or left axel I pull everything and nothing,so I un-mounted the differential opened it and everything is perfect and turns smooth, What could it be? the Transfer case?

can some one tell me what could be wrong. my car is not running.
Thanks
pepeancon

 

[410Fortune]

What made you replace the differential in the first place?

 

[Creager]

could be a ujoint

 

[V8BoatBuilder]

Check the bolts between the t-case and the front driveshaft. Or, for troubleshooting, remove the front shaft completely, and go on a test drive.

 

[Flash]

Sounds like the CV joints.

 

[Nitrous SSC]

FYI The pinion gear gear on the flat side of it has which ratio it is.

Dumb thing to check but I'll throw it in. Check the brake caliper bracket bolts, where it bolts to the spindle assembly. It can make some really loud knocking noises when it gets loose. It will get loose unless you do a minimum of 80-90ft-lbs with lock-tite.