Build of my JKU

BaddestCross

Active Member
So can someone please explaine to me why I now need a longer drive shaft with the prorock 44 if the Jeep is sitting in the exact same height and control arms are damn near the same? Is is shorter pinion or something?

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You said you aimed the pinion at the t-case now? Do you have pics since the changes were made?



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 

MericaMade

Active Member
You said you aimed the pinion at the t-case now? Do you have pics since the changes were made?



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
Ok here are some. This was the last picture I took before I turned the uppers out one more turn to get the driveline straight. The closet I got to go off of for now.

Right now lowers are set at 23 inches and uppers are set to 19 inchs center bolt to bolt.

Caster at 7 and pinion at 4.

What am I missing? 20200512_175938.jpg 20200512_175950.jpg 20200512_180002.jpg 20200512_180009.jpg

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MericaMade

Active Member
You still need to turn up your pinion to point to the transfer case. Lengthen the upper control arms a bit.


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You're angle is the red line. It should be closer to the blue.
View attachment 347397



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
Thank you for that. It's closer to that blue line now after that picture but I willl turn out the upper arms even more and get back to you with a updated picture.

Just questions not second guessing you guys but In my head by turning the uppers out even more, isn't that going to strech the driveshaft out more?

And even thought DT says to keep a 2-4 degree pinion angle should I just ignore that and make sure my pinion and driveshaft are straight regardless if it ends up being 5 to 7 degrees?



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Last edited:

BaddestCross

Active Member
Thank you for that. It's closer to that blue line now after that picture but I willl turn out the upper arms even more and get back to you with a updated picture.

Just questions not second guessing you guys but In my head by turning the uppers out even more, isn't that going to strech the driveshaft out more?

And even thought DT says to keep a 2-4 degree pinion angle should I just ignore that and make sure my pinion and driveshaft are straight regardless if it ends up being 5 to 7 degrees?



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Turning the uppers out pushes the pinion up which shortens the length of the shaft. Are your lowers set so that your bump pads on the axle are centered with the bump stops? If not, you should shorten the lowers to get the correct location of the axle and then adjust the uppers for the pinion angle.



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 

MericaMade

Active Member
Turning the uppers out pushes the pinion up which shortens the length of the shaft. Are your lowers set so that your bump pads on the axle are centered with the bump stops? If not, you should shorten the lowers to get the correct location of the axle and then adjust the uppers for the pinion angle.



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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
Yes on the bumps, I checked that a few times. I will make more changes on pinion tomorrow.

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JKbrick

Active Member
I always thought the front went by caster and had nothing to do with pinion angle? That’s why the PR44 has more angle built in to it is what was explained to me. But I don’t have one either so I really don’t know. If you bought it from Bubba you should call him


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jeffj

Caught the Bug
I always thought the front went by caster and had nothing to do with pinion angle? That’s why the PR44 has more angle built in to it is what was explained to me. But I don’t have one either so I really don’t know. If you bought it from Bubba you should call him


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You are correct, it’s your caster not pinion angle. The pro rock will make your pinion angle better but set your caster where you want it and then measure for correct length drive shaft. Good luck, try to keep it simple.


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MericaMade

Active Member
You are correct, it’s your caster not pinion angle. The pro rock will make your pinion angle better but set your caster where you want it and then measure for correct length drive shaft. Good luck, try to keep it simple.


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I was focusing on 6-8 caster but that is not working for me. Today, I am just going to set the pinion to a zero degrees to the shaft per others advise here and see if the caster stays in specs.
 

fiend

Caught the Bug
The driveshaft angle looks better. Vibrations gone?

Your 5 degrees of caster is still better than the stock 4.2 degrees.

The shaft is definitely too short. FWIW, I have 1” of splines showing.


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MericaMade

Active Member
The driveshaft angle looks better. Vibrations gone?

Your 5 degrees of caster is still better than the stock 4.2 degrees.

The shaft is definitely too short. FWIW, I have 1” of splines showing.


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Well, the angle looks great now, but that does look like way too much spline. I don't have a tape handy, but it looks like I've only got about 1.5" or so exposed.
View attachment 347434




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Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
No haven't driven it yet. There is only 3 inches of spline in the yoke. I'm gonna take it to Inland Empire Driveline tomorrow and see what they say.

I do feel good about the pinion angle now.

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jdofmemi

Active Member
No haven't driven it yet. There is only 3 inches of spline in the yoke. I'm gonna take it to Inland Empire Driveline tomorrow and see what they say.

I do feel good about the pinion angle now.

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I can't believe there is 3" of spline engaged. The amount of spline showing is barely less than the length of the yoke. I would be very hesitant to drive it like that, and those who know me see me as a risk taker.

I have also had a driveshaft separate at speed, and can tell you you don't want to go through that.
 

MericaMade

Active Member
I can't believe there is 3" of spline engaged. The amount of spline showing is barely less than the length of the yoke. I would be very hesitant to drive it like that, and those who know me see me as a risk taker.

I have also had a driveshaft separate at speed, and can tell you you don't want to go through that.
So, apparently per Dynatrac the PR44 housing is shorter than a stock 44 and that is where that shaft lenght issue is. I must have miss that some where along the research.

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