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Discussion Starter · #1 ·
So my xj makes a very loud and very annoying whining noise at 45-50 mph. Almost sounds like someone blowing across a bottle top. It has been doing it for a couple months now, getting worse as time goes on. Sounds like its coming form under the dash. Is not effected by cruise control, a/c on or off, fan on or off. Any Ideas?
 

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check your unit bearings by jacking up the front end and pushing the tire back and forth (12 and 6 o'clock) and check for movement. also, make sure you have fluid in your t case and diff.

i would also check the play in the pinion of the front diff. push up and down on it and see if it moves, then figure out whats causing it, most likely the bearing is shot.
 

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Yeah since they're full time 4x4, the front end and drivelines always turn, mine does the same cause i dont have the front ring and pinion set up exactly to spec......it could be a number of things....but if you can FEEL it, like in the steering wheel or floorboard, then you know its something in the drivetrain.
 

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its not his r&p, and not the unit bearings...i checked them today. its not a "whine" but more of a whistle
there is a grommet under the dash on the pass. side that likes to come lose all the time. check that. also, he may have a whole in the floor board???
 

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Where be the whistle?

To help narrow down whether it is drive train or not...does it stop after exceeding 50 or so, or does it do it at any speed above 45? If you or a passenger pops your head out the window, can you hear it outside more or less (despite the wind noise in your face). If you get in the dryer of a carwash, does it happen? Maybe the wind is hitting something just right and we could rule out drivetrain. Any variations when speeding up, slowing down, or coasting in neutral?
Weird issue.
 

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My 95 made that exact noise after 120k miles on the original diff fluid. as soon as i changed the fluid it stopped getting worse(still there though). Just like you said, 45-55 ish.

Charlo
 

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Discussion Starter · #9 ·
some updates...

I do not feel it when it happens, I just hear it. My diff fluid was changed 40,000 ago so i don't believe it is that. It is a 2000 in really good condition so there is no holes in the floor boards. It is now doing it from about 40 to over 70 mph (not that i ever go that fast :smokin:).

Could it be a pulley going bad? the belt? or even the electric fan? Remember it only does it at speed, never happens while idle.
 

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No fans

If it were a pulley or a fan, you would be able to duplicate it without moving between revving the engine (to get pully speed)and turning the A/C on (to get the electric fans on). Conditions on those things will be virtually unaffected by actually moving.
I assume that if you floor it while whistling to down-shift and up the RPM, the whilstle is unaffected? If it is, you can rule out the pullies.
Tcase and Transmission fluids fresh and full?
 

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I assume that if you floor it while whistling to down-shift and up the RPM, the whilstle is unaffected? If it is, you can rule out the pullies.
Tcase and Transmission fluids fresh and full?

Same line of thinking, anything above 45 it whistles? Does it get worse when the engine RPM's change or if you go from driving side to the coasting side of the gears?

If it doesn't change it sounds just like a simple wind noise by a piece of trim or something if the only factor that causes it is purely wind speed.
 
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