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Loud Grinding Noise Upon Acceleration

F

fubar XJ

NAXJA Forum User
Location
Bothell, WA
I apologize if this has been covered, a search proved fruitless. Upon hard acceleration, my '91 XJ 4.0L makes a loud clattering/grinding noise, which lets up immediately when I let off the gas. Sounds almost like a detonation-type noise, but recently it makes an actual louder noise more akin to a grinding. The engine has 200K miles, otherwise runs and drives fine.


Any thoughts?
 
CHECK YOUR TRANMISSION MOUNT. PLACE A LIFT JACK WITH A PIECE OF WOOD TO AVOID DAMAGE TO TRANS OIL PAN AND LIFT SLIGHTLY AND OBSERVE THE MOUNT ABOVE THE CROSSMEMBER. IT MAY LOOK GOOD AT FIRST BUT IF APPEARS TO SEPARATE WHEN LIFTING, ITS BAD AND MOST LIKELY YOUR PROBLEM. I WENT THROUGH THE SAME THING UNTIL I FOUND OUT THE POSSIBILITY OF A BAD MOUNT ON THIS FORUM. DOING THE LIFT TRICK WILL PROVE IT GOOD OR BAD.

CHECK THIS THREAD: http://www.naxja.org/forum/showthread.php?t=912822&highlight=TRANSMISSION+MOUNT

HOPE IT HELPS YOU TOO
 
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My '93 has made what may be a similar noise for the two years that I've had it. There was a thread some weeks ago about noise on acceleration caused by a worn transmission support crossmember. You might search for that thread, perhaps with "crossmember" or "transmission". Mine hasn't been enough of a nuisance so far to check this out as a possible cause.
 
TRUST ME, IT WILL GET WORSE, NOT TO MENTION STRESS CRACK YOU MOTOR MOUNTS TOO. THE FIRST TO GO WAS MY DRIVER SIDE. AND IT WAS ALL ONLY JUST OVER SEVEN YEARS OLD!
 
dude, step away from the caps lock.


anyway, to the original poster.
does it still make any noise when coasting?
is the noise coming from the motor, or do you feel hear it in the body underneath you?

check the trans mount, then check the driveshaft u-joints, then pull the rear driveshaft and drive it in 4wd with just the front shaft.

If the noise goes away when you pull the rear shaft it's something there, if it stays, then it's something in your t-case, trans or front driveline.
pull the front driveshaft and drive with just the rear, if it goes away the cardan joint likely wants rebuilding in your front shaft, if it remains, then it's not in the driveshafts, and likely it's in the trans or t-case.

provided of course that you've eliminated the motor as suspect, but from your description it sounds like a driveline noise.
does the motor make that noise in neutral and free revving?
 
I don't think this has been asked yet but, is your XJ lifted? If so it could easily be driveline vibrations from binding u-joints.
 
SORRY FOR THE CAPS!

The way he decribed it was directly on the button as what happened to me, under hard acceleration and all. The detonation sound was the rib built into the mount was contacting the rest of the metal structure of the mount due to the rubber failing. I can supply a pic if needed to see what I mean. I do hope for Fubar's sake that it is the mount. Like I mentioned before, test the mount with the jack (so far the easiest test) then I would follow 87manche's advice to narrow it down.

"dude, step away from the caps lock."

I'm just trying to help out here CAPS LOCK or not, besides, thats what we're all here for, or so I hope, to seek, find , then share our experience as help for other forum members benefit, grammar, spelling, or word fomAT aside. I'm not fuming to you personally, but I get that alot since I broke my hand and am forced to type with one hand, it gets old to me to keep reaching for the shift key to properly capitolize the needed letters. DAMN, THIS IS WHY I GOT MY JEEP IN THE FIRST PLACE. TO GET AWAY FROM PEOPLES' PETTINESS! AND NOW HERE? F

:flamemad: :twak: DAMN BIPOLAR PROBLEMS DON'T MIX WELL WITH PETTY PROBLEMS. Dont mind me just pissed i cant work on my jeep with my f-d up hand. just thought helping someone with their needed help would keep me content, guess not. LATER


 
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LR_2000_XJ said:
SORRY FOR THE CAPS!

The way he decribed it was directly on the button as what happened to me, under hard acceleration and all. The detonation sound was the rib built into the mount was contacting the rest of the metal structure of the mount due to the rubber failing. I can supply a pic if needed to see what I mean. I do hope for Fubar's sake that it is the mount. Like I mentioned before, test the mount with the jack (so far the easiest test) then I would follow 87manche's advice to narrow it down.

"dude, step away from the caps lock."

I'm just trying to help out here CAPS LOCK or not, besides, thats what we're all here for, or so I hope, to seek, find , then share our experience as help for other forum members benefit, grammar, spelling, or word fomAT aside. I'm not fuming to you personally, but I get that alot since I broke my hand and am forced to type with one hand, it gets old to me to keep reaching for the shift key to properly capitolize the needed letters. DAMN, THIS IS WHY I GOT MY JEEP IN THE FIRST PLACE. TO GET AWAY FROM PEOPLES' PETTINESS! AND NOW HERE? F

:flamemad: :twak: DAMN BIPOLAR PROBLEMS DON'T MIX WELL WITH PETTY PROBLEMS. Dont mind me just pissed i cant work on my jeep with my f-d up hand. just thought helping someone with their needed help would keep me content, guess not. LATER
Click to expand...
Whoa there man, take er easy. I'm pretty sure he was just messin with ya. You've gotta learn to take a little bit of crap or you're just going to frustrate yourself around here.
 
LR_2000_XJ said:
TRUST ME, IT WILL GET WORSE, NOT TO MENTION STRESS CRACK YOU MOTOR MOUNTS TOO. THE FIRST TO GO WAS MY DRIVER SIDE. AND IT WAS ALL ONLY JUST OVER SEVEN YEARS OLD!
Click to expand...

this is dead on what happened to my jeep.
 
j99xj said:
Is your A/C on? If so your belt is probably just too loose. Same thing happened to me.
Click to expand...

Wow, where did this come from? Loose belts squeal, no grinding's gonna come from that.

As for the caps lock thing. No biggie, ease up.
 
JJacobs said:
Wow, where did this come from? Loose belts squeal, no grinding's gonna come from that.

As for the caps lock thing. No biggie, ease up.
Click to expand...

It was just a suggestion. Mine made a horrible sound (whatever you want to call it). I've found that its much easier and cheaper to check the easy things first (like a drivebelt). If the drivebelt isn't his problem then it must be something else that would require parts and labor. But at least at that point we know its not the belt.

Bottom line: check the easy stuff first. Throwing more and more money on a problem doesn't fix it unless it is correctly diagnosed. (apparently the damned government thinks so, unfortunately)
 
Perhaps the clutch fan is grinding against the shroud or radiator. Amusingly, this is also caused by bad motor and tranny mounts. Replace and post back...
 
darjevon said:
Perhaps the clutch fan is grinding against the shroud or radiator. Amusingly, this is also caused by bad motor and tranny mounts. Replace and post back...
Click to expand...

I thought about it later yesterday, it sounds like it is the fan contacting the shroud, bad trans or motor mount. I didn't get a chance to check either of those last night, but I will. It makes sense, motor lifts on acceleration due to a worn mount, fan contacts shroud and makes whirring or grinding noise. The Jeep is not lifted yet, kit's on the garage floor awaiting some other work. I'll be checking into all three mounts in the next couple of days and squaring it away, thanks for the input guys.
 
Yeah mine did that - the fan ate the shroud and radiator under heavy accel, grinding like hell - and I wasted no less than 3 RADIATORS before I figured out what the damn problem was. (yes, i was an idiot.)
 
My header pipe is a bit loose where it mounts to the transfer case crossmember which is also the same place as the flange which mates the Catalytic converter to the header pipe. The result is the same noise you are describing. It can come and go, depending on how the engine is idling, how warm the metal is etc etc. Most of the time as I pull away from a stop sign it'll make the same grinding sound you describe, or as I'm pulling hard up a hill.
I havn't bothere fixing it yet, since I'm lazy.
 
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