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Old February 14th, 2022, 09:55 PM
Prowbar Prowbar is offline
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Default Re: Drivetrain noise

Quote:
Originally Posted by AZKen View Post
Do you mean the splines of the slip yoke or the Ujoint of the slip yoke?

Put your hand on the trans shift tower, where stick come out and see if you feel the noise. Stick shake.
You are an engineer, you know about natural frequency. This can be similar. You mention it starts at a certain RPM and stops and another. This makes me think of amplitude, resonance. High frequency "rattle" sounding like gear or bearing problem, but is not.

The 2, 3 and 4th gears are helical and don't make much noise. But they go make some noise. Noise at 1:1 is said to either be normal in SM420 or bearings. Additives may quiet it. Lucas is said to be best.
Old trucks with all metal cabs and no sound deadener, have always made noise. They are a huge transmitter.
Make sure ujoints are phased.
Slip yoke splines. U joints are new.

U joints are phased now, I am going to turn the splines 180 degrees and see if that helps any. Then they are still phased but mirrored.

Thanks for the help, Ken. I will go out and experiment some, I'll report back my findings.
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