If you're installing a suspension lift on your truck, there are many different components to think about. One of the components that you should evaluate is the drive shaft. Few suspension lift kits have new drive shafts, but you may find that your truck benefits from an upgrade. Here's a look at what you should know about how the drive shaft is affected and how you can measure the truck to get the right size for your new one.
How The Drive Shaft Is Affected
Your truck's suspension is designed with a specific geometric structure that allows the springs, joints and shafts to work in harmony. When everything sits at the right angles for the suspension, the truck rides smoothly and everything responds correctly as you turn the wheel either direction.
Every time you engage four-wheel drive, the drive shaft that connects the rear axle to the transfer case engages and starts to turn. That shaft is the single connection that ties the rear axle to the transfer case, so it plays a vital role in your four-wheel drive function. If it doesn't connect at the proper angle, it could bind up or put too much pressure on the shaft itself.
This can occur any time you install a lift because it alters the center of gravity and the truck's ride height. Over time, the change in geometry can actually cause wear on the joints at the end of the drive shaft. This can cause the shaft to fail, costing you your four-wheel drive and potentially damaging the axle..
How To Measure For The New Drive Shaft
Install the rest of the suspension system before you measure for the new drive shaft. This ensures that you have the proper distance measurements from the new suspension geometry. After the lift is installed, raise the truck with jacks and support it with jack stands secured on the axle shafts.
Look for the U-joint that attaches to your truck's transfer case by the rear axle. Use a measuring tape to get the measurement from the flat side against the transfer case to the flat edge of the differential in the center of the axle. Write down this measurement.
Measure across the U-joint cap as well, which is the "U" positioned at each end of the drive shaft. Make sure you measure both of them so that you get a shaft large enough and with a wide enough U-joint to fit the mounting points. Learn more here.