By now you may have heard or read somewhere about CV eliminator or conversion drive shafts. Many OEM driveshafts consist of constant velocity (or CV, for short) components that are used to correct high angles while still allowing the drive shaft to maintain a constant velocity during rotation. This is often done by vehicle manufacturers to ensure smooth operation in all-wheel drive vehicles. What the manufacturers normally do is install the same constant velocity shaft throughout the rest of the vehicle lineup (even the vehicles that are not all-wheel drive). A great example of this is with the 2001-2003 Dodge Durango R/T vehicles. These have what is known as a Rezeppa style CV front prop shaft. Instead of using a different drive shaft for standard 4X4 Durango and Dakota, they installed this Rezeppa style shaft in all of the vehicles.
Here is an example of a Dodge Durango/Dakota front drive shaft. This Rezeppa style driveshaft was installed in all Dodge Durango and Dakota vehicles, regardless of all-wheel drive capability
Though these drive shafts work great when the vehicle is new, they eventually wear out and begin to fail. This leads to vibration and eventual loss of four wheel drive/all-wheel drive capability.
So What is a CV Eliminator/Conversion Drive Shaft?
Most of the time an all-wheel drive vehicle requires some form of constant velocity assembly in the front drive shaft to ensure smooth operation. However, on 4X4 trucks and SUV's that aren't all-wheel drive, but still have a Rezeppa shaft, you can often replace the OEM driveshaft with a CV eliminator/conversion shaft. These are drive shafts that have flanges installed that will actually install in same mounting location as the Rezeppa CV assembly but are machined for traditional universal joints. This allows for a more simplified, durable drive shaft that is user-serviceable with easy to source universal joints.
This picture shows a CV eliminator/conversion drive shaft for the Dodge Durango/Dakota. Notice the six-bolt flange that bolts into the cup style yoke in place of the Rezeppa CV head that is found on many Dodge Dakota and Durango vehicles.
Is a CV Eliminator Right for My Vehicle?
This question depends on whether or not your vehicle is all-wheel drive capable. As a general rule of thumb, if your vehicle is all-wheel drive, you'll need to either replace your drive shaft with either an OEM driveshaft or aftermarket equivalent. In some cases, you can replace the pinion yoke at the transfer case with one that will accept a standard double cardan constant velocity unit. Many customers have found that the "old school" style CV that comprises two universal joints, a centering H-yoke, and a center bearing to be far more durable than the Rezeppa assemblies.
If your vehicle is non all-wheel drive, yet 4X4 capable, you can usually replace that Rezeppa shaft with a CV eliminator that will give you years of trouble free use.
Other Vehicles that Benefit from CV Eliminators
A prime example of a vehicle that benefits from a CV eliminator shaft is the 1995-2003 Chevrolet S-10/GMC Sonoma. The models that come from the factory with the two-piece drive shaft with the dual constant velocity assemblies on the rear section can definitely use a CV eliminator drive shaft. Like with other conversions, the replacement drive shaft is adapted to the mounting points on the vehicle by way of a flange that is machined for standard u-joints. These drive shafts have proven to be far more cost effective and durable than simply rebuilding the constant velocity assemblies that come stock from the factory. Additionally, most conversion drive shafts are a simple drop-in replacement. If you have any questions, please feel free to ask us!