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Pinion angle changed

Chris

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Okay, so I had my rear driveshaft angle at about 16 degrees and the rear pinion was at about 15 degrees when I completed the my Currie suspension install. I never noticed any vibrations until today because I hadn't been at highway speeds until now. Anyways, I noticed over 40 mph it definitely vibrates. I went to check the pinion angle in the parking lot just now in the rear and my pinion is now definitely higher than it should be, noticeably too.

Has anyone ever ran into something like this where once things settled in, the angles changed slightly?

I assume that being off only by a few degrees in the rear would be enough to vibrate?

I'll have to measure the angles but just by eye balling it I would say the shaft is at 16 degrees and the pinion is around 18-19 degrees. It's noticeable looking at it from under the vehicle.
 
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Chris

Chris

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Eh, I was wrong. The rear is fine and I checked the angles to verify. I am still getting vibrations though which means they must be coming from the front driveshaft. There's no other explanation.
 

Jerry Bransford

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I dunno Chris it's hard to tell from the photo but it kinda looks like the pinion angle could be a tad high.

Exactly where did you measure the pinion angle from?
 
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Chris

Chris

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I dunno Chris it's hard to tell from the photo but it kinda looks like the pinion angle could be a tad high.
It would seem that way, but I measured it and the pinion angle is a little less than 1 degree lower.

Do you think it's possible that my front driveshaft might need to be re-balanced after the lift?

I'm puzzled here. If the rear angles are good, that really only leaves the front.
 
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Chris

Chris

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Where did you measure the pinion angle from?
See the photo attached (excuse the fact that it isn't a TJ, I just found this image and Photoshopped it really fast.

You can remove the front driveshaft to verify if the vibrations are coming from the rear.[/QUOTE]

Yes, that was my thought... But... As we discussed the other day, I think this requires dropping my transfer case skid, which at that point I may as well just wait for my Savvy transfer case skid to get here and kill two birds with one stone.
IMG_0295.png
 

Stinger

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See the photo attached (excuse the fact that it isn't a TJ, I just found this image and Photoshopped it really fast.

You can remove the front driveshaft to verify if the vibrations are coming from the rear.


View attachment 2007[/QUOTE]
Interesting. I set the angle finder on the diff cover bolts and the shaft. Then work with the degrees of angle difference. Same results I suppose but by using the bolts it gives the angle finder a larger foot print
 
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Chris

Chris

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Thanks Jerry. You've still got to measure the driveshaft angle though, right? If so, where are you measuring the driveshaft angle from?
 

Jerry Bransford

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Thanks Jerry. You've still got to measure the driveshaft angle though, right? If so, where are you measuring the driveshaft angle from?
From the driveshaft. But I usually just eyeball the angle between the driveshaft and pinion. I actually seldom dig the angle finder out of the tool cabinet.
 
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Chris

Chris

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From the driveshaft. But I usually just eyeball the angle between the driveshaft and pinion. I actually seldom dig the angle finder out of the tool cabinet.
Yes, I was speaking to MUDB8 about this and he was telling me the same thing, that there's really not even a need for the angle finder since you can usually just eyeball it.

He had mentioned that it's possible my front driveshaft could need to be balanced. I guess the first thing to do is unbolt it and drive without it to see if that's the issue. However, that requires dropping the transfer case, so I suppose I ought to just wait until my Savvy skid plate gets here otherwise I'll have to do it all over again.