What's worse than finding out that a CV boot has torn on your machine while you're deep into a great day of riding? Well, I guess there might be a few things. While rocking out some hard miles on our Arctic Cat Prowler 650 in the backwoods of northern Georgia, we experienced a torn boot which eventually evolved into a destroyed rear axle. This can be a common occurrence, and CV boots need to be inspected on a regular basis. As we have stated in the past, it doesn't take much wear or exposure to the elements to get down into the heart of a constant-velocity joint. Once the rear wheel stopped turning, we knew it was time to replace the axle. And in typical ATV Rider fashion, we documented the action for our readers.
Important Note: These instructions are meant to complement the use of the OEM service manual and shouldn't be performed without one. The tips in this article should be part of a general guide for axle servicing and don't contain important information like torque specs or procedures that are specific to your ATV. You can pick up an OEM service manual at your local dealership.
First, clean up a large area in the shop or garage and make sure the quad is clean as well. This way you don't create more problems by getting the internals of the rear transmission filled with dirt. Place your side-by-side on a reliable jack. You don't want one of these to come crashing down as a result of a cruddy jack.
Tip
Be sure to have your OEM service manual handy for torque specs when reassembling. Our procedures are meant to merely simplify the procedure as directed in the service manual.
Tip
While you have the CV joint out of the knuckle assembly, it's a good idea to check the bearings in that knuckle. Do this by rolling them back and forth, while feeling for any rough spots in the movement of the bearing.
Tools Required
Clean shop, impact wrench (if you have one), metric wrenches, needle-nose pliers, OEM service manual, rubber hammer, anti-seize product, lipstick form or brush-on applicator, large floor jack, patience
Summary
A properly functioning CV axle is essential to operating your ATV or side-by-side. To save a little money, purchase the recommended CV axle from your manufacturer or aftermarket company and try replacing it yourself. It's not an extremely difficult procedure, but check your service manual in conjunction with our step-by-step guide to ensure a trouble-free installation.

Grab an impact wrench or socket...

Grab an impact wrench or socket wrench and begin loosening all four lug nuts. Now remove the tire and wheel and set them to the side.

On our Arctic Cat 650 H1,...

On our Arctic Cat 650 H1, we needed to remove the cotter pin and axle nut first before trying to remove the wheel hub.

The next step is to pull off...

The next step is to pull off the hub and unbolt the knuckle assembly. There are two bolts, one on top and one on bottom. This allows the knuckle to pull out toward you.
Tip
Using a rubber or dead-blow hammer ensures that you won't nick or scar the metal surfaces while coaxing an axle in or out of the knuckle assembly.

Now you need to slip the knuckle...

Now you need to slip the knuckle back over the wheel-side end of your new CV axle and reassemble. You may have to bump the knuckle on with your rubber hammer.

After persuading the wheel...

After persuading the wheel side of the CV joint out of the knuckle, use your dead-blow rubber hammer to work on the main axle shaft.

Reach for the new axle assembly,...

Reach for the new axle assembly, and make sure to add a little differential oil or grease to the seal before reinstalling into the transmission.
Tip
When reinstalling the new axle, add a touch of anti-seize liquid to the axle splines to ensure the hub will not corrode and become stuck should you have to remove it again. It's good to do this with your wheel lugs as well.

After aligning the splines...

After aligning the splines on the axle, it will slip into the transmission with little effort. The circular clip on the axle will compress and then snap into place when it finds the cut in the receiver.

Remove the remaining axle...

Remove the remaining axle by pulling it straight out from the side. The axle can be coaxed from its fixture by simply tugging on the end closest to the wheel. This may take a few tries to be successful, but it will come out.

Install the wheel hub, axle...

Install the wheel hub, axle nut and cotter pin. Reinstall your wheel, let down your trusty jack and roll the machine forward and backward just a bit to make sure it moves freely.
Tip
Always replace the used cotter pins with a new one. If you stress the cotter pin upon removal, it may wear prematurely and fall out.