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Axle picture request

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Whiskerbiscuit

Whiskerbiscuit

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If you know the vibration frequency and road speed, then you should be able to calculate what component it is (or isn't) related to.

For example:
- 63 mph = 332640 feet/hour = 3991680 in/hour = 1108.0 in/sec
- Your vibration is at 18 cycles/sec
- If it is happening once per revolution of the component (that's a big IF), then the component must be turning once for every 61.6 inches traveled. Not sure what that could be, but it isn't the gear mesh frequency of the ring gear.
Correct if you read up in the post I said I have a vibration of or around 15-19hz which is tire rotation speed at 63mph... your driveshaft at that speed should be around 40-60hz if I remember. Hz = cycles/sec

Tires, axles, and ring gear spin at this speed.

Driveshaft, pinion, and transfer case spin at a much more variable frequency due to engine speed.
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jac04

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Correct if you read up in the post I said I have a vibration of or around 15-19hz which is tire rotation speed at 63mph...
Well, I didn't see anywhere where you stated that, but you need to check your math.

If your vibration is at 15 Hz:
63 mph = 1108.8 in/sec
(1108.8 in/sec) / (15 cycles/sec) = 73.93 in/cycle
There is no way your tire has a circumference of only 73.93 inches, which is a diameter of 23.53".

If your vibration is at 19 Hz:
63 mph = 1108.8 in/sec
(1108.8 in/sec) / (19 cycles/sec) = 58.36 in/cycle
There is no way your tire has a circumference of only 58.36 inches, which is a diameter of 18.58".
 

ShadowsPapa

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Bone stock. But looked at my axle and a few on the lot and mine is slightly different.

20220626_195549.jpg
If it's stock, no driveshaft change, the angle won't matter. Only matters with cardan type u-joints.
These are a type of CV and there's no change in the shafts rotational speed if the joint is operated at an angle.
Don't sweat the angles, look for bends, something damaged, out of balance, and so on.
I chased one for a very very long time - and it was a wheel even though the lateral runout was fine and 2 tire shops and an axle shop even looked at it after I threw my hands up.
 

ShadowsPapa

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it can be done, just don't lift it 5' in the air, a few inches off the ground and common sense, if the thing starts to jiggle shut it down. Or set it up on jack stands.

Not all shops have dynos.
I set my 4x4 car on stands, solidly placed under the axle housings. 4 stands, 6 ton rating each.
That way nothing was hanging at weird angles (with the very short drive shafts in the SX4, any angle on the shaft can be really nasty since it has cardan joints and angles are critical on it)
Of course it behaved just fine because it only did it when the weight was on the road.
 

rharr

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I set my 4x4 car on stands, solidly placed under the axle housings. 4 stands, 6 ton rating each.
That way nothing was hanging at weird angles (with the very short drive shafts in the SX4, any angle on the shaft can be really nasty since it has cardan joints and angles are critical on it)
Of course it behaved just fine because it only did it when the weight was on the road.
Agreed that is one potential outcome and part of basic trouble shooting.
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