Long time lurker, first time poster. Search has given me no leads so far, so here's my mystery.

One day on the freeway my stock '95 XJ started emitting a noise from the front that sounded like metal flapping in the wind. Dropping speed below 65 mph would make the noise go away. Finished my trip (a little slower) and parked the jeep until the next weekend. Took it out again, and now the same noise starts around 40 mph. It sounds like something is bouncing and flapping in the wind, but the intensity doesn't change much with speed. At first I thought my front license plate was flapping....not it. Next I found my grill a little loose, so I secured it....still nothing. I found what I think is a charcoal or vacuum canister inside the front bumper that has come loose.....not it either.

The drive train feels fine, but I also know I have an undiagnosed issue with the 4WD. I haven't looked far in that direction because it would have to be a ujoint, axle, or something in the front diff if it's related to 4WD and it just doesn't sound or feel like the drive train.

Not RPM sensitive. Applying brakes makes no difference. Accel/decel makes no difference. Going over bumps changes nothing. The noise comes in around 40 mph and only intensifies a little if I run it up to 70 mph, and then goes away again below 40. No vibrations or popping. Turning makes no difference.

Any guesses or similar experiences?

 

Can't think of a thing. No vibration in the steering wheel? A noise related to a particular speed tells me an imbalance is the problem. Perhaps a hub bearing has decided it's had enough and begins talking at 40 mph.

 

Some catalytic converters have a heat shield, check that. They often rust.

Check the backing plate on the front disc brakes to verify they are not rusted and not moveable.

Do you still have the engine splash shield? These often tear and then could flap around.

Check if the hood release cable might be vibrating against the hood. Newer XJ's don't have hood insulation to help.

Check that the bracket that holds the accelerator, cruise control and AT kick down cables to the valve cover is secure.

The shroud for the fans often rattle and squeak. They looesly set into the lower radiator support with a couple of friction clips

 

third coast might be on to something. Both radiator shrouds are loose and it's plausible that the noise is coming from one or both. I'll secure them tonight and take a test drive. Worst case, I'll record the sound if that doesn't cure it.

 

No dice. I did manage to record it though.

My rattling Jeep

 

I posted that video quickly last night from my phone. Forgot to mention that it was taken at 45 mph. Going faster only makes it slightly louder.

 

Have you checked the engine and transmission mounts? Check out Cruisers post here: https://www.cherokeeforum.com/f2/200...1/#post3580445

 

Hard to tell from the recording - you definitely don't feel any related difference?

From the description I'd definitely think it's a loose panel, heat shield, etc.

How are the hinges on your door? Do you feel any draft near your shins or up at the top? Could it be one of the mirrors? I know my mirrors on my 95 are pretty floppy.

Jack up the front and spin the wheels by hand - look at the front driveshaft and see if there's any roughness in either wheel turning. Try to wiggle the wheel at 12 and 6 and 3 and 9 and see if there's any play.

 

You might check the belt driven fan and fan clutch. They are designed to partially disengage and free wheel at certain conditions. It might be more speed dependent than engine RPM dependent. If you do some searching you can locate tips to check it. They apparently tend to fail with age/miles.

 

Maybe the electric fan shroud? Something in your ashtray? An empty washer fluid container with some lug nuts thrown in for good measure?

 

Mounts are solid.

There is no feedback through the steering wheel. It sure does sound like something loose flapping around. Definitely not the doors or mirrors. Drive shafts and ujoints appear fine. No play in the wheel bearing.

The way I understand the fan clutch is that it engages based on temp. My fan clutch appears ok, and the noise doesn't care if the engine is up to temp or not. Definitely speed dependent.....RPM makes no difference.

That is an accurate description of the noise! Wasn't the source, though. I thought I was on to something with the driven fan shroud, so I removed it and went for a drive.....rattle rattle rattle.....

It was loose anyway so I also removed the plastic air dam (or whatever it is) from just below the bumper....no change. From the drivers seat it sounds like it's originating from somewhere between the fan and the front passenger wheel. I'm wondering if something is rattling around in the front diff? Or maybe the transfer case chain?

 

Loose exhaust possibly? It has a tendency to knock against the crossmember (around the front passenger seat area).

 

where is this being recorded from? inside, out the door, under?

 

Exhaust is solid and effectively ruled out.

Taken from drivers seat.

I went on a couple more test drives and the sound is starting at lower and lower speeds. Definitely getting worse. I discovered that if I open my door while going down the road the noise is extremely loud and sounds like metal clanging on metal directly below me. I thought it wasn't in the drive train, but now I'm thinking it is related to my 4WD issue, which I suspect is the t-case chain. Tonight I'll drop the front drive shaft and see if it makes a difference.

 

I’ve been down with a cold for the past week but i found the noise today. After I pulled the front drive shaft I was able to freely turn the output yolk of the transfer case by hand. I could hear the chain dragging and slapping inside. Went for a test drive....no more noise. Definitely coming from the TC.

I already knew 4wd didn’t work right. Lots of grinding if engaged. I bought it that way. I engaged it a couple of times just to hear the issue for myself and I think I pissed it off. Looks like a rebuild is next move, but at least I can drive it now.