Hum in Front End

amslube · **Posted:** Mon Dec 15, 2014 9:27 am

I've been noticing a hum coming from the front end which started a few weeks ago and seems to getting a bit louder. Sounds like a noise generated by an aggressive tire thread pattern but I've got Cooper Discoverer CTS tires, an all season thread, on the CRD for about 6 months now with no cupping or uneven wear. There was no tire noise when these were installed. There is no vibration noticeable in the steering wheel. I'm leaning towards front hub bearings until I get a chance to jack it up and check it out this week. There is 115K miles on the Jeep and has been a very reliable vehicle so far...with many of the tweaks suggested on this forum.
Can anyone else who had hub bearings go describe their experiences? Thanks...

Pippobug · **Posted:** Mon Dec 15, 2014 10:07 am

Sound like hub bearing. If you haven't changed them until now you have done well. I am now on my third set at the front with 135K miles but I am also lifted 3.5" so a bit more stress there.

amslube · **Posted:** Tue Dec 16, 2014 10:42 am

Did some diagnostics yesterday. I jacked up the rear off the ground and ran the rear wheels and heard no hum. Jacked up the front end so all 4 wheels were off the ground, put the transfer case into PT 4WD, ran up to 50mph and the hum was there so it's from the front end. When jacked up I couldn't feel any play in the front bearings or any roughness when spinning the wheels, but unless the bearings are totally shot, I feel this would be the case. Front shafts appear fine also, no play or slop and boots intact. I ordered a pair of Timkins and will replace them soon. Looks like an easy process. I like repairing/replacing worn parts before catastrophic failure.

flash7210 · **Posted:** Tue Dec 16, 2014 11:25 am

Did you order hub assemblies or just bearings?
Replacing the entire hub assembly is fairly easy.
Pressing off and on individual bearings is not.

amslube · **Posted:** Tue Dec 16, 2014 5:03 pm

Ordered the hub assembly.

flman · **Posted:** Tue Dec 16, 2014 6:49 pm

When my LTD did this a few years back, I rotated the tires front to back and the noise moved with them.

If the hub bearings are bad the noise will be more pronounced when you make a turn one way, and less pronounced the other. End of story.

amslube · **Posted:** Tue Dec 16, 2014 9:07 pm

Had all 4 wheels off the ground, put in gear and ran speed up to 50mph, and only in 4WD had the hum. I felt this discounted tire noise.

flman · **Posted:** Wed Dec 17, 2014 9:54 am

amslube wrote:

Can anyone else who had hub bearings go describe their experiences? Thanks...

When I went around a turn with the bearing loaded it was noisy, with no load it was quieter. Every vehicle I have ever seen with a bad hub bearing did the same thing.

Did you check all the axle fluids? I hope the hubs do it for you if you are going that route.

amslube · **Posted:** Wed Dec 17, 2014 11:42 am

Axle fluids are fine. New Timkin hubs arrived today and will install early next week.

amslube · **Posted:** Tue Dec 23, 2014 2:30 pm

I replaced both front hubs today with Timkins...hum is gone. When hubs were out you could feel the slight roughness when turning them in hand. The left side was a bit worse than the right.
Now developed a slight coolant leak...noticed a couple of drops on the garage floor the other day. Preliminary investigation today after I finished the hubs appears the leak is from the drivers side possibly in the area of the EGR valve. Saw this from under the vehicle. Didn't have time to look further today.

papaindigo · **Posted:** Tue Dec 23, 2014 4:30 pm

UV coolant dye can be helpful in locating leaks like that but I'd suspect a weak hose spring clamp or the small EGR cooler hoses which are known to leak. Those hoses can probably be replaced with regular hose of the proper size or since you have a GDE tune you can simply bypass the EGR cooler entirely by routing the feed and return lines into a loop.

flman · **Posted:** Tue Dec 23, 2014 5:52 pm

Glad that all worked out for you, never had 2 hubs go out at once.

jws84_02 · **Posted:** Tue Dec 23, 2014 6:23 pm

I replaced both of mine at the same time just cuz I figured if one was on its way out the other wasn't too far behind. I didn't realize how bad mine were until I put the new timkens on and how much quieter it had gotten

amslube · **Posted:** Tue Dec 23, 2014 10:06 pm

I hope it's just a hose or hose clamp but if it is the EGR cooler a bypass will certainly do. This will have to wait until Friday or over the weekend.

My thinking on the hubs exactly! If one is making noise the other can't be far behind. And mine were not at the point where I could feel which one was bad when on the vehicle but once out could feel the bearing roughness in each.

Took the CRD out this evening to a party and even the wife commented on how quiet it was.

Hum in Front End

Who is online