Driveshaft alignment |
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Clint
Member Joined: 12 Sep. 2018 Location: Earth Status: Offline Points: 28 |
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Posted: 17 May 2021 at 3:38pm |
No arrows on the driveshaft. Put it back together with new u joints
Now there’s a vibration. Isn’t there only one way because it’s splined one way? Or am I missing something?
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SE Kansas 46 CJ-2A
Member Sponsor Member x 3 Joined: 22 Jan. 2016 Location: S.E. Kansas Status: Offline Points: 3192 |
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You are missing something. There are two possible ways the slip yoke could go on the splined shaft and on a dynamically balanced shaft there is really only one way. This is the correct driveshaft phasing:
This is incorrect phasing: If you install the the correctly phased driveshaft it shouldn't vibrate unless it has been damaged or has a binding u-joint installed in it. If it still vibrates after correcting the phase, take it out and install the slip yoke 180 degrees from your first installation. Edited by SE Kansas 46 CJ-2A - 17 May 2021 at 4:05pm |
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46 CJ-2A #64462 "Ol' Red" (bought April 1969)(second owner)(12 V, 11" brakes, M-38 frame, MD Juan tub)
U.S. Coast Guard Chief Petty Officer(ret.) U.S. Army Vietnam veteran and damned proud of it. |
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Clint
Member Joined: 12 Sep. 2018 Location: Earth Status: Offline Points: 28 |
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Thanks! I’m on it!
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lowenuf
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Please help me understand the only two ways that you referenced .... The slip yoke can be installed onto the splined shaft in any of the 360 degree rotational splines, there is no indexing on the internal nor external splines. The "arrows" that are always spoken of only serve to properly phase the two ends when mated...... Unless I am misunderstanding your anology....
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45 #10012
45 #10033 ACM #47 45 #10163 ACM #188 57 CJ5 Dauntless V6, T-18 4-speed, D-44 rear/D-30 front, D-20 twin stick |
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SE Kansas 46 CJ-2A
Member Sponsor Member x 3 Joined: 22 Jan. 2016 Location: S.E. Kansas Status: Offline Points: 3192 |
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Actually, there are sixteen splines on the driveshaft and the yoke could be installed in any of those ways. There are only two choices where the correct phasing will be evident.
My attempt to explain phasing of a driveshaft was perhaps not involved enough. Yes, the slip yoke can go on multiple ways, but only two ways yield a correctly phased driveshaft. If a driveshaft has been dynamically balanced, there is only one way that the driveshaft will probably operate without vibration; that is if the yoke and spline stub are installed together just the way it left the balance machine. A 180 degree phasing may or may not yield a satisfactory vibration free operation depending on how lop-sided the slip yoke is. The lower photograph that I showed in the above post illustrates the most common phasing mistake made while installing a driveshaft. Any other of the possible ways that a slip yoke could be installed on the spline except as illustrated in the top picture is out of phase and could possibly introduce vibrations into the driveline under operation. There are extreme industrial applications that involve severe driveshaft angles where the driveshafts are purposefully designed out of phase to cancel bad harmonic vibrations but those are exceedingly rare. To my knowledge Jeep never used a factory installation of an out of phase driveshaft. If an out of phase driveshaft is going to cause a vibration problem it will more than likely be the rear driveshaft because of the angle the driveshaft has to operate at. Front driveshafts in a flatfender usually don't cause vibration problems even if they are out of phase because the angle is shallower, unless the splines and yoke are worn out or one or both of the u-joints is worn or binding. Full disclosure: I built or repaired hundreds of driveshafts during a 18 year period where I owned and operated a shop that also repaired truck transmissions of all sizes, transfer cases, axles, and power take-off gearboxes and shafts. I closed the shop in 1995. |
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46 CJ-2A #64462 "Ol' Red" (bought April 1969)(second owner)(12 V, 11" brakes, M-38 frame, MD Juan tub)
U.S. Coast Guard Chief Petty Officer(ret.) U.S. Army Vietnam veteran and damned proud of it. |
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