Front end noise after wheeling. metallic scrapping tapping with speed.

Hey guys. I have an issue I thought I would run by the good ole boys at .

Went wheeling at a place called rancho this weekend and ended up with a few issues. for one my front end diff knocked a hole in my down pipe but the one that has me baffled is this noise from the front end.

It only makes the noise when im moving so its hard to isolate by myself since i cant inspect things while im driving obviously. seems to get worse after things are warmed up. i can hear it best when the motor isnt under load. like when im coasting. its a metallic scrapping and its not a constant sound but more rhythmic and varies with speed and stops when the jeep is stopped.

brake performance hasnt changed. suspension feels the same. i got real muddy that day but the trip also consisted of various terrains if that matters. spent most the day in 4hi.

ideas???

oh yeah, '93 4.0 aw4 np231 d30/8.25 6.5" short arm lift with drop brackets

thanks guys

hub assembly(wheel bearings)? Mine made the same noise you are explaining right before 4 or 5 of the ball bearings shot out haha.

it can be pretty loud. how long do you think i have before they go out?

ive got some spares. ill swap 'em out and see if it helps.

If thats what is making the noise, Depends. When I started hearing the noise they started puking bearings all the way home(17 miles or so)

You said that your differential knocked a hole in your exhaust downpipe? Maybe you meant the front driveshaft? Have you checked to see what might have broken to allow the front DS to impact the downpipe--engine/transmission mounts?

joe_peters said:

You said that your differential knocked a hole in your exhaust downpipe? Maybe you meant the front driveshaft? Have you checked to see what might have broken to allow the front DS to impact the downpipe--engine/transmission mounts?

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i think i need bump stops. i was driving at a pretty good clip up one side of a ditch. i just think the suspension compressed too much at the right angle but ill look into it. i see where you're coming from.

i have replaced the wheel bearing and it didnt fix the problem. im almost 100% positive the noise is coming from the double cardan joint on the front drive shaft.

Pull the front DS and drive it, noise gone you've found it. The OEM downpipe is "mashed" to clear the front DS, usually after a lift it isn't a problem and you can use a "round" downpipe, if your bumpstops are adequate.

i have a borla header and downpipe and there is a rip in the front of it right above the bend. looks like the lip on the diff housing where the yoke comes out hit it just right. and i have no bumpstops. i honestly feel both problems are separate and coincidental.

i will be pulling my front DS before i go pull one at the junkyard to use as a core. so guess ill find out then. i hear the double cardan joints are a pain to work on so i figured it'd be easier to go pull one. i tried to disassemble one before and ended up with a mess.

one thing i noticed today, i have more vibes at high speed than i did before.

front DS replaced, no noise. thanks guys.