Driveline Geometry

One of the most common causes of torsional vibrations has to do with driveline angles between the transmission and front and rear drive axles. Since your drive axles may be a long way from the engine and transmission-and probably at a different height-the number, length, and height of the driveshafts must be varied. These varying heights and angles can create torsional vibrations throughout the drivetrain, which in turn can cause vibrations that reduce drivetrain component life (and noises that can drive your drivers up a wall). They also make it virtually impossible even for a seasoned technician to visually inspect a driveline and see whether its component angles are going to lead to problems down the road.

Eaton offers its Roadranger Driveline Angle Analyzer (DAA) Tool Kit that helps you easily measure, diagnose, and correct driveline angle problems in medium- and heavy-duty drivetrains. The kit consists of a series of special tools, including software on CD-ROM with printable worksheets, a digital protractor that automatically displays driveline angle settings, a tube diameter gauge, two U-joint rulers for both Spicer and Meritor driveshafts, and even a 25- foot tape measure to determine driveshaft lengths. The kit costs around $400, and the CD-ROM is available separately at approximately $50.