Humming noise at all speeds

So I got myself a humming at all speeds and I don't know where it's coming from. I got a 2000 XJ sport 4.0L 4WD with HD leaf packs in the rear, front axle swap to a HP dana 30 with 3.55 gears off a 1997. teraflex 2" BB and an OME tcase drop for 2-2.5 inch lifts. I just put +2 skyjacker shocks in the front but not the rear yet. The noise gets progressively louder as I accelerate but gets quiet quickly when I let off the gas. I can relate it to hearing my gears spin because as I go down in speed the noise level and tone goes down too. I got some low tread hancook HT tires on there and one of them is beat up from the accident I had in december. It drives, but I don't want to ignore this humming until it becomes a bigger issue. I have already pulled the front shaft and it's not that. The tires are balanced (even the one tire that's kind of shredded) The Ujoints were just changed a couple months ago. I'm thinking it's a driveshaft issue or a gear issue somewhere. Does anyone have a clue? This XJ must be saved!

I'm thinking tire tread you said one was chewed up

The reason its humming?





It doesnt know the words.

Rear diff bearings? How many miles on rear end?

Ron

Could be tire noise or noisy hub bearings. I had no play on my hubs but they were noisy. Replaced with new Timken units and all was quiet.

Is there a test I can do to test the hub bearings?

The tires are low on tread and that tire is in the rear driver side its chewed up in the sense that it looks like someone cut some extra lines into it because it got shoved into the fender and that cut it up a little while I was driving

If the hub bearings are noisy at speed, you probably won't be able to tell just by spinning by hand, because you won't be able to rotate it fast enough or under load. Of course you can test for any play by jacking up the front so the tire is off the ground. Check for play by grabbing tire at 3 & 9 o'clock positions and pulling back and forth, also check at 12 & 6 o'clock positions. People will say any play at 3 & 9 position is from hub bearing and play at 6 & 12 is from ball joints. Not always true! I have had a hard time discerning minor bearing play at 3 & 9 position, but could feel it at 6 & 12 position. If you have play at 6 & 12 position, pry up bottom of tire with a pry bar and block of wood while looking at the ball joints for play, to determine whether its ball joints or hub bearing play. If you find any play at all with the hub bearings, just replace them both. Hope this helps.

FWIW, I had a problem on my 99 like that, turned out to be the front hub bearing.

I had the same problem a few years back, until I kicked my girlfriend out.

What do you mean with 3 and 9 o clock positions? what am I turning or looking for play in? where are the hub bearings? I only know what simple things I've done so far. When it comes to troubleshooting or electrics, I'm lost in the sauce.

The humming is louder and higher pitch the faster I go. I feel it in the pedals like a phone vibrating and slightly in the steering wheel.

I cant really get rid of the girl. She has that whole shiny on the finger.. she just wants me to get another car

Box kicker said:

What do you mean with 3 and 9 o clock positions? what am I turning or looking for play in? where are the hub bearings? I only know what simple things I've done so far. When it comes to troubleshooting or electrics, I'm lost in the sauce.

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You grab the tire at those positions and pull back and forth to see if there is any play.

The hub bearing sits behind the brake rotor and is mounted to the knuckle with three bolts from the back.

Lots of good info at www.stu-offroad.com , if you have some mechanical ability, read up and start doing some repairs you will be better at keeping your Jeep going.

Alright, I think I got the jist of how to do it. I just wiggle it without turning the wheels pretty much?

Are these things I have to replace on both sides or can I just do 1 side? I can't get to it today. I probably have to replace all the joints, bushings, and bearings since I got the axle from a junk yard.

Yes, just do one side at a time.

I'll try to get it checked tomorrow, are there any limits to which it's acceptable for play? so if only 1 side is bad I don't have to replace both? or are they like springs and shit where you have to do both sides or it gets lop sided or something?

If one is bad its best to replace both, i always replace in pairs, lights hubs tires i don't care always both sides imo. If one is going out, chances are the other isn't too far behind

Yeah, I guess. There is no way to truly get some cost effective maintenance. Plus it would eliminate the problems. Well if it persists, I will probably start a new thread about all of it with more trouble shooting steps. I appreciate your help!