The kiss of death for any FWD halfshaft is a damaged, torn or loose CV joint boot. Why? Because it means the CV joint will soon lose all of its grease and self-destruct from excessive heat and wear. A leaky boot also will allow dirt and water to get inside the joint and cause further wear and corrosion. So once a boot starts to leak, it won’t be long before the joint fails and the shaft needs to be replaced.
The replacement market for halfshafts is a big one. About 85 percent of all the cars on the road today are front-wheel drive, and some are all-wheel drive (which doubles the number of shafts per vehicle). Many trucks, SUVs and CUVs that have 4WD or AWD also have halfshafts similar to those on passenger cars.
The service life of a FWD/AWD/4WD halfshaft depends on how long the boots hold up, and the kind of driving the vehicle is subjected to. Hard use and lots of turning will wear the CV joints at an increased rate.
As the inner and outer CV joints on the halfshafts wear, increased play causes noise and vibration. The outer joints usually experience more wear than the inner joints, and usually fail first. A classic symptom of a bad outer CV joint is a clicking or popping sound that’s heard when turning. A clunk or vibration that is heard or felt when accelerating or changing speed, on the other hand, usually indicates a bad inner CV joint.
Although inner and outer CV joints can be replaced separately, it’s a messy labor-intensive job to disassemble and rebuild a halfshaft. It’s much easier and faster to simply replace the old halfshaft with a new or reman halfshaft.
Reman replacement FWD/AWD/4WD halfshafts often are sold on an exchange basis while many new shafts are sold outright (no core charge and no greasy exchange shafts to handle, store and ship back to a rebuilder).
The replacement market for halfshafts is highly competitive, and today there’s not that much difference in price between some new shafts and reman shafts. Reman halfshafts may come with reground CV joints, new CV joints or a combination thereof depending on what’s needed to rebuild the shaft. Remanufactured CV joints are precision ground (not hand-ground) on state-of-the-art computer-controlled equipment. The joints are then reassembled with new oversized internal components (balls and cage, and race if required), and a new boot.