Re: Cv boot torn!!!
Like Frank said, dirt is the problem and the fact that the greese will leave the joint when the boot is torn. A damaged boot can go unnoticed for awhile because you may not know what or when it happened, then you factor in normal wear and a host of other things that can shorten the life of a CV joint, you just don't know how long it will last.
You can buy a boot kit, which comes with a new boot, a packet of CV joint greese and the two end clamps. Depending on the kit, you may need the tool to install the clamps as well. If you Google CV joints, you can find all kinds of information about CV joints, cleaning an old one, packing the special greese and installing a new boot.
If you are buying a new CV joint with the axle shaft, make sure you get the right one for your Jeep. The dealer will want your VIN number which tells them what you have. If you go to a parts dealer, they may ask you things like Quadra Drive, Vari-Lock which is part of Quadra Drive or Dana 30 or other things. The main thing is to get the right part. I have read where a guy here at the forum got a CV Joint and shaft and it didn't seem to fit right. He mentioned he was going to have to do it again. I have been dealing with a noise that I feel sure is coming from the left front wheel. It comes with tire rotation and not drive shaft rotation. Trying to figure out what it is before I get dirty. Finding out about CV joints has kept me busy a couple of days now. So just make sure you get the right one.
My problem has turned out to be an embarrasment. I did have a noise and it got louder as I continued to try figuring it out. I went out and drove in tight circles in both directions. I drove by windows trying to watch the rotation of the tire with realtion to the noise. I had my Jeep up on stands with the wheels running. I hand turned the drive shaft. hand turned the wheels. Nothing showed up without the strain of the wheels driving the Jeep. It turns out that I had 4 loose lug nuts on the left front tire. Yes, lug nuts. The 4 were loose enough for me to turn them by hand and yet one was still tight enough to keep me from feeling the tire and wheel being loose. I have the chrome plated Rogue aluminum wheels. I now know how important it is to torgue those wheels when I rotator the tires. I was lucky that I didn't have something happen on the road or that the vibration could have damaged something else. So far so good.
Anyway, at least put on a new boot. That will be a lot of work, but it could save you in the long run.