Hello all, I am pretty new to the XJ world. A couple months ago I installed a 3" lift that knocked my driveline angles all to crap and I am just now getting it fixed. Finally drive it with no vibrations coming from the rear driveshaft, only to hear a very strange noise from the front end. The best way I can describe it is a sort of humming/rumble noise that is definitely coming from the front end. The location of the noise makes me think of a dry front diff, but the noise only occurs when I am pressing the gas and I would assume if it were something to do with the front diff, the noise would be constant when the wheels are turning. I took the front driveshaft off and drove it and the noise changed, but didn't totally go away. I put the vehicle up on jack stands and drove it up to 60mph and the sound was no where to be heard, so it has to be something with the turning of the front wheels. Wheels and tires were just balance so I do not believe it is unbalanced tires. I've browsed the forum for similar problems but can seem to come up with anyone that has had a similar problem so I'm hoping there is someone that can help!

 

Usually front wheel bearings would be more pronounced when slowing or turning. But it may be worth checking quick anyways. Vibrations and sounds travel strangely sometimes. My ears have tricked me more than once on where sounds are coming from..
Also, have you actually checked both diff fluid level? Transfer case fluid level?
You could also rotate your tires and see if noise changes just to be more sure it's not a tire.
bad U joints would usually cause vibration with noise, but again worth a quick check anyway while under there. Check all of them, driveshafts and front axle.

That's some of the stuff I would do anyways if it were mine. Check all the easy stuff even if it doesn't seem like it would be the culprit.

My only other idea is there is still an issue with the driveline angles. I don't have any experience in working with that though my jeep was already lifted when I bought it and didn't have angle issues.
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I had the same problem it's gotten bad not trans mount or front end like it sounds checked driveshaft have no idea not trans mount joints look fine tinyest bit of play not enought to make the sound it's making haven taken the drive shaft out yet cause I'm worried I'll hurt tcase cause it fulltime AWD I can't afford to hurt it