Big Lift? New Transfer Case? Different Transmission? Most major changes like this are going to require new drive shafts for your toy. In many cases your current shafts can be shortened or lengthened but in others a complete new drive shaft will be required. Drive shaft work is not something that most backyard mechanics can take-on at home. The rear Drive shaft is especially critical since it is always spinning and much of that time is at high speed. The front drive shaft is not as critical as it is generally only spinning when in 4wd and this generally occurs at slower speeds. This is NOT always the case though as was with our full-time 4WD transfer case that originally sat underneath our Tahoe.

The drive shaft requires very precise construction and proper balancing to prevent vibrations. For some help we turned to Six States Driveline. Six States has many shops located around the West Coast. We located the nearest one to us in Pasco Washington and called in their expert for some help.

Rear Drive shaft

The top picture shows the new Double Cardan joint. Bottom is the original single cardan with internally splined slip yoke.

Before we changed to our new transfer case the rear of our Tahoe had a Slip Yoke Drive shaft with a single cardan joint on both ends. Our new rear shaft from Six States is a slip member shaft with a 1310 CV ( or Double Cardan) on the transfer case end and a single cardan on the other end. The slip member shaft is more desirable for off-road use and was the standard on older 4x4's. The 1310 references the size and strength of the joint. A 1350 series is larger and stronger and commonly found on 1-ton trucks. The double cardan CV joint is much better at eliminating vibrations in your Drive shaft This will allow the Drive shaft to run much smoother and put less stress on all of the driveline components The downside is that the double cardan joint is much more expensive. Pay now or pay later?

With single cardan joints at both ends you generally want to rotate or shim your axle to achieve equal angles at both ends. This would put your pinion shaft and your transfer case output parallel with each other. With a double cardan joint on one end it is much easier to achieve proper geometry as you want 0 angle on the pinion side and the pinion shaft should be inline with the slope of the Drive shaft That said you need to remember that those angles are the operating angles. Most 4x4's experience some axle wrap which rotates the pinion shaft up 1-2 degrees.

Above: Proper Geometry for a Drive shaft with single cardan joints on both ends. Below: Proper Geometry for a Drive shaft with a Double Cardan joint.

Front Drive shaft

The front Drive shaft on our Tahoe was an externally splined slip yoke shaft with a double cardan joint on the transfer case side and a single cardan joint on the pinion side. We had changed to this Drive shaft when we lifted the Tahoe due to the full-time 4WD transfer case which spins the front Drive shaft all the time. With our new NV243 transfer case our front Drive shaft will only spin when in 4WD. The angles are not very severe so we went with standard single cardan joints on both ends. If you have a much bigger lift you may want to go with a more expensive CV style shaft in the front also. The new shaft is a slip - member style shaft since the NV243 transfer case uses a standard yoke.

Front Drive Shaft: On the top is our original drive shaft and on the bottom is our new Six States drive shaft.

Six States Drivelines

Whatever your Drive shaft needs are, Six States can build a shaft to fit your needs.We found Sharky at the Pasco, WA office to be very helpful as we worked through the process. Six States uses genuine Spicer products when building drive shafts We have used other u-joint products in the past but nothing compares to the quality of Spicer products.

Summary

We installed our new Six States drivelines and were back in business again, sorta. We are only rear wheel drive. We still are working on the wiring issue with the new NV243. It also looks like we will need to get a TCCM (Transfer Case Control Module) from the NV243 doner vehicle. We will update the project as soon as we get this electrical problem worked out.

Enjoy!