Grinding noise, frt. end, 91 4X4

kelikran · 05-08-2008, 07:35 AM

I get a nasty grinding noise, will start when going over a rough spot, most likely at speeds under 60 km/hr, although I have had it at 90km crossing onto a bridge that was rough. Lasts anywhere from 1-2 secs. to 5-8 secs., just quits on it's own. If it is at low speeds, slowing to almost a stop makes it quit. I have pulled and checked both hubs, they are working properly and released as they should be. I have jacked up both front wheels, they spin freely, with a slight amount of pull, just as they should. There is no side to side play. I can't feel anything wrong there, and can't see anything either. When the grinding happens, there is a definite braking force happening. I guess the next step is wheel bearing replacement, but I didn't know wheel bearings could start out intermittent like this, I thought when they go, they just go. Any ideas from anyone? This is really bothersome, and I would also be concerned about driving it, except that, like I said, they feel tight and turn fine when jacked up. There is something triggered by just the right kind of impact going over a rough spot.

jtgh · 05-08-2008, 02:55 PM

that is wierd.
id have hubs off and look inside. almost all are bad. neglect is PO's motto.

what ever, it sounds bad, not something that will get better , only worse.
hope it is something safe going bad. like finder falling off and not critical driveline stuff.

96GeoTracker · 05-09-2008, 01:51 PM

Sounds kind of like the wheel bearing, We have a Ford Explorer and right after we got it there was a noise kinda like your talking about and it was the wheel bearing going out.

captchee · 05-09-2008, 05:19 PM

when was the last time you checked the breaks ?
the front disks have metal tabs on them that are there to warn you when the pads have warn to much . they will intermittently grind on other vehicles so i would bet they would on yours as well .
the other thing to look at is your CV joint boots . Are there a crack or tear . if so they could be making a grinding sound. From contaminants getting in the join .

as others have said , look at your bearings as well but it would surprise me . normally when a bearing starts to go , it will growl pretty constant ,then squeal in its final death throws .
also while you have them out . look closely at the spindles for signs that they have been damaged.
Last but not least, if all looks well , frown real hard , cross your fingers and drain the differential .
Catch all the oil . Look closely for metal fragments . If non show up at first , dip our finger in the oil .
Then take a look in the bright sun light . If the oil looks heavy sparkly , you have a front or rear bearing that’s spinning or going out in the diff

kelikran · 05-10-2008, 12:13 AM

Thanks for the replies. JTGH says hubs off to check. Did that first thing. Or does he mean whole thing, bearings and all? Haven't had time to go that far yet. Brakes, maybe, but it doesn't happen during breaking. And always triggered by pothole, rough spot, or washboards. Driving about 10 miles one way to work on gravel roads these days. Will happen a couple of times during each one way trip. As far as wheel bearings go, like Captchee says, once they start, they should grind constantly until it's over. Also, I'm 90% sure it's coming from the front left wheel area, so I don't think front diff. Actually, it
can't be the diff, because nothing is turning there. When I get it checked out, I will post, for all you fellow 91 ers out there, there seem to be lots of us. Going to bed,have to work again tomorrow. Adios.