grinding problems

well, my first cherokee was a 93 and it lasted till 266,000 miles. god rest its soul, its now gone. but i have got a new cherokee to play with. its a 94 sport 4x4. i bought it about a week ago for a steal. anyway. everything works great on it. i noticed today as i was going about 40, there is kind of a grinding sound. i know the wheel bearings make a vibrating sound, but not a grinding. i dont think its the brakes becasue they were just done. i dont know what else it can be. ball joints?
thanks

94' Cherokee Sport 4X4
4.0 High Output I6
AW4 Transmission
NP-231
3 in. Rough Country w/ 31X10.50X15

got back from colllege the other day and drove my cherokee for a bit on the highway. and theres a vibrating sound coming from the front end. i think that it is just the wheel bearings. there is also 31's on it. could they just be making the sound. i have a 95 wrangler with 33's and they make a vibrating sound on the highway. is there anyway to test a wheel bearing to see if something is wrong.
thanks

Do you feel a vibration in the front end? The axle U-joints will make a bad vibrating noise and feel in the front end, you will feel it coming up through the floor and seat, and the noise sounds like a wheel bearing but not quite as loud, more of a vibration rather than just a sound like a wheel bearing.

I'd check out those front axle u-joints. I'm in the process of doing one now. The joints cost about $12 each, if you do it yourself.

i checked the axle u joints when i bought the jeep. that was the problem with my brothers wrangler. his are like, completly gone in the front and the click and its really annoying. mine are strong and dont move irregularly. but im not a big mechanic. i do everything at trial and error and once i know how to do it, its not a problem. this is tapping into the "dont know how to do yet" section. so i dont know if its the joints or not. its not a bad vibrating sound. more like a soft humming sound. but u can sort of feel it in the front. to see how bad it is, i took it 85 on the highway and there was slight vibration. but i know that larger tires can do that just like it did with the 33's on my brothers jeep so. im going to put 235's back on it tomorrow and see if theres a difference. if not, ill take a look at the u joints and wheel bearings
thanks
Patrick

Most likely both bearings wouldn't be bad at the same time, you can always tell a bearing by turning the car, if it gets louder on right turns, it's the left wheel bearing, and vise versa. The pressure gets put on the outside wheel when you turn, so whichever one gets louder when it's the ouside wheel is the bad bearing.

But a u-joint will be loud and vibrating going straight, and it may only start to vibrate at a certain speed, like 55mph and anything under or over that won't be as bad. If it is really bad, like mine, it will actually grind when you are acclerating from a stop.

i dont hear anything more when i am turning at all. it just seems that it has a little hum to it. it does it through all speed ranges. at first i thought that it was something grinding on the suspension. but the more that i listened to it, i it seems that its just vibrating or something. so i dont know. ima give it a look tomorrow to see if it is doing the things that you described.
thanks
patrick

Your vibration at all speeds, this could be from the tires, and incorrect camber alignment. Check the inside of your tires, are they worn to and erregular chop pattern? If so this is the problem. Also to effectively check you driveline for possible cause of your vibration, put the jeep on a rack or get all 4 wheels off the ground. Put it in 4 hi, drive, then run the speedo to about 40 -50(makesure your stands are STRONG and SOLID) have a friend with good hearing, walk around and listen to the wheels. If you have a wheel bearing problem you should be able to pin point it. Or a driveline issue.

well my "mechanic" thinks that it is just my oversized tires. the dumb kid that owned it before me didnt know what he was doing and put 31's on a stock suspension. i expect that he didnt get an alignment with the new tires. so no alignment and the combination of the oversized tires i believe is making the vibration/humming sound. i dont have 4 jack stands to do the test you described and i didnt have time today to put the 235's on it to see so i will just do that tomorrow and i will let you know what i come up with.
thanks
patrick

ok. well i just put 235s back on it and it ran the same way. i jacked up the front end and put my hand on the spring. i didnt feel any vibration on the drviers side, but the passenger side had a slight vibration. then i had my brother wiggle the tire up and down and left to right. the drivers side didnt move, but the passenger side moved. the ball joints werent moving on either side.i could see anything moving on the drivers, but the passenger, the axle was moving down. is that the wheel bearing? how long can i ride on it this way for like a month? what would happen if it does fail completely.
thanks

It sounds like the wheel bearing, recommend getting a big,long pipe and a 1/2" breaker bar with a 36mm socket. You'll need this to break the axle nut loose. Oh and get a torque wrench that goes to 200 ft lbs. Torque on the axle nut is crucial.

ok. combination of college and lack of funds halted the fix. however, the new wheel bearing is on there now and it is still making a vibrating sound. now its only happening from 55-65 mph (the wheel bearing was shot, there are no longer any grinding problems). its kind of a vibration...........vibration...............vibrat ion. kinda like the ring of a phone. as in it happens like every 5 seconds and lasts for 5 seconds, etc. my front end shakes a little everytime and yes, i can feel it on the floorboard with my feet. any suggestions?
thanks

May be an imbalance of your front driveshaft. If it is bent in the least, you could feel it. It is actually quite easy to pull the front DS, and then drive around like that for a bit to see if there is any change. At the very least you can rule out a few more things.

Axle U-joints is my bet. What makes you think they are fine, especially after they had 31's on them?

they dont click or anything. how do i check to see if they are bad or not?
i jacked up the front and the u joints turned freely. i dont know how to check to see if that is my problem or not. thanks for the help guys. keep it coming.
thanks
patrick a ruth

You need to grab either side of the U-joint, and try to move the shaft parts in/out, up/down, and twist back and forth. There should be zero movement. Any that move are bad/worn. This goes for front axle U-joints, and front and rear drive shaft U-joints, including the double cardigan joint in the front DS, if yours has one.

If none of these are causing your grinding, you may be getting into a more expensive problem.

i rotated my tires today and now there is NO vibration coming from the front end. it must have been my tires being unbalanced. now the front are on the back. so i might get them rebalanced when i get sum $$$. thanks for the great help you guys.
patrick a ruth

I need to figure out the gear ratio on my 96 jeep cherokee and I'm not real smart about these sort of things as you can see. Could one of you nice folks please tell me how to go about it? I'd surely appreciate it.........

I need to figure out the gear ratio on my 96 jeep cherokee and I'm not real smart about these sort of things as you can see. Could one of you nice folks please tell me how to go about it? I'd surely appreciate it.........
Welcome to AF.

You should start a new thread on this subject, to get the best response.

Raise the rear axle and support it on axle stands, so the rear tires are off the ground. Rotate the rear tires (both together) exactly ONE rotation and count how many rotations the driveshaft makes. You will end up with a ratio, so just over 3 driveshaft rotations means your ratio is 3.08:1.
3 and a quarter rotations = 3.23:1
3 and a half rotations = 3.54:1
etc, etc.