A lot of guys, updating their trucks' drivelines, ask about driveshaft pinion angles, shaft length, critical speeds and other related drivetrain stuff. A lot of info and advice out there is incomplete, confusing or just plain wrong. Here's Grigg with some straight dope on ...
Duh!!! Read the Instructions!
Most people have a hard time understanding how a driveline should work. Therefore many people who think they know how to set it up are confused.
I have found that the best way for someone to understand how it works, and how to set the angles, is to read the instructions.
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These two manuals will help with all driveshaft installation and geometry questions. Personally, I have printed them both and put them in a notebook that's very handy: "
- Driveshaft Installation Guideline, Spicer manual number DSIG3311
This one is most useful when reinstalling or slightly modifying an existing driveline. It will help with figuring angles and ideal operating conditions.
- Spicer Driveshaft Applications Guidelines, Spicer manual number DSAG0200
This one is most useful when designing a driveline from scratch. It will help with figuring critical speeds, max shaft lengths, and required component sizes for any given application.
The Basic Rules
Some important parts cut and pasted from the "Installation Guide" (first of the two links above):
- Rule #1 -- Universal joint operating angles at each end of a driveshaft should always be at least 1 degree.
- Rule #2 -- Universal joint operating angles on each end of a driveshaft should always be equal within 1 degree of each other (1/2 degree for motor homes and shafts in front of transfer case or auxiliary device).
- Rule #3 -- For virtual vibration free performance, universal joint operation angles should not exceed 3 degrees. If they do, make sure they don't exceed the maximum recommended angles.
Please read the manuals -- you will learn something and be glad you did!
Good engineering is simply finding the right wrench
to pound in the correct screw.
Adam Welchel, 1947 Chevy