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Discussion Starter · #1 ·
Well, I am forced to cross-post this question. Need help picking a pinion angle. I am at the stage where my 8.8 axle is ready for brackets. I have a set picked out, but I am still trying to figure the pinion angle I need. I did the string test whereby I ran a piece of string from the center of my existing axle to roughly the end of the tcase output shaft. I measured that angle at a scant 7 degrees or so. Does that sound correct? This is about half of the lowest angle I've read others going with. However, I am only running a 2.5" suspension lift and 33's. I'm going to add adjustable upper and lower control arms plus a SYE and Tom Woods shaft. Is my paltry lift the reason I seem to need such a shallow angle?
 

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Genius
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Well your pinion angle will have to change when you go CV/SYE.

In stock form your pinion angle needs to be the same as the output of the t-case. (i.e. the mating surfaces should be parallel to each other.

When you go CV/SYE you point the pinion straight at the output of the t-case and then lower it 1-2*.


This should help you understand what I'm getting at.
http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html
 

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I originally set mine up for 17 degrees . I have been slowly been lowering it since but doing other mods to keep the same amount of suspension travel to basically lower the center of gravity . I now have 2.5" progressive rate springs and a 3/4" spacer . I have a 14 degrees on the driveshaft and 13.25 pinion angle . I would say if you set yours up at 15 initially you will plenty of adjustability to lift more if you want later . I would get 4 adjustable control arms so you can set it close and fine tune it with the arms .I also still have a 1" mml installed so that actually lowered my output shaft some but I'd say 15 would be a good ballpark figure to set up the brackets .
 

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Discussion Starter · #5 ·
Boy, this is a conundrum! Thanks for the replies. Lots of stuff to study. 15* really? That just seems so (too) steep. Again, when I measured from the end of the tcase to the center of my existing axle, I get 7*. So, if I set at say 15* with adjustable control arms (x4), I can still dial it in without having to worry too much about the angle of the spring perches? CG
 

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I set mine to 17 figuring 4" of lift . I am no about 3.25 and have adjusted it down to a little over 13 . Its easire to lower it from what I can see . If you have to increase it with the arms you risk the track bar bracket hitting the fuel tank . In some cases the diff cover contacts the skid to begin with . they all come out a little different so I try to leave myself plenty of adjustibility . I also have a 1" mml lift so I could remove that and increase the angle if it was needed also

read these two article until you are confident in what you want .

Ford 8.8 Axle Install - 1

8.8 FACTS, OPINIONS & HOW-TO'S (F.A.Q.) - JeepsUnlimited.com Forums
 

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Discussion Starter · #7 ·
Yes, this is the heart of my confusion. When I "mock" a SYE/CV setup under my current rig, I get an angle of seven degrees. Off to study! CG


When you go CV/SYE you point the pinion straight at the output of the t-case and then lower it 1-2*.


This should help you understand what I'm getting at.
Pirate4x4.Com - Extreme Four Wheel Drive
 

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Genius
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I'll try and explain this in a bit more detail.

To set up pinion angle on CV/SYE setups I use a framing square and a magnetic angle finder and just the angle finder for non-CV/SYE setups. Any kind square will work but my framing square is about the same length as the drive shaft so it makes lining things up easier for me.

Non-CV/SYE:
Place the angle finder against the end of the output shaft on the transfer case and record the angle. Then place the angle finder against the yoke or flange on the 8.8. You will then adjust the 8.8 so that the angle on yoke or flange is the same number as what you wrote down from the transfer case. For example if you wrote down 9*(this is just a random number) then you would adjust the 8.8 till you are at 9*.

CV/SYE:
Using the framing square or what ever set the 8.8 so that the center of the pinion is pointed right at the center of the end of the output shaft on the transfer case. Then with the angle finder measure the angle at the yoke or flange on the 8.8. Then adjust the 8.8 down 1* or 2*. For example when you place the angle finder on the 8.8 and get an angle of 21*(again just a random number) then you would adjust the 8.8 to either 20* or 19*.

I hope this helps.
 

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i have the CV/SYE and set mine to 18*, running a 4" lift and full adjustable CA's, but since im feeling some drive line vibe's i need to do some adjusting soon, possibly transfer case drop to "straighten" out my issue... Sooo ive essentially added nothing of value to this thread,ha ha :blunt:
 

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i have the CV/SYE and set mine to 18*, running a 4" lift and full adjustable CA's, but since im feeling some drive line vibe's i need to do some adjusting soon, possibly transfer case drop to "straighten" out my issue... Sooo ive essentially added nothing of value to this thread,ha ha :blunt:
shouldn't need to drop TC thats one of the benefits of a SYE . you pinion angle may need some adjusting . Check the pinion angle in relation to the DS , it should be a degree less than the DS use the adjustable control arms for the fine tunimh part.
 

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Discussion Starter · #11 ·
I think I have finally wrapped my feeble brain around this. I plan on installing some manufacture of SYE and a custom Tom Woods drive shaft. I was hoping to be able to figure out my pinion angle soon, so I can go ahead and start the bracket welding. But it almost seems I may need to have said SYE installed--or at least in-hand-- before I can find "my angle". I'm thinking of a simple mock-up whereby I have the SYE and position the 8.8 at the proper distance and height that it will have upon install, and do my measuring in a controlled environment. Or is this overkill? I want to get this as close as possible to perfect.

Also, is there any reason to lose my motor mount lift when going with the SYE/CV, or just leave it be?

Thank you all so much for clearing this up. CG

Happy Christmas! War Is Over. Oh, wait.......:(
 

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shouldn't need to drop TC thats one of the benefits of a SYE . you pinion angle may need some adjusting . Check the pinion angle in relation to the DS , it should be a degree less than the DS use the adjustable control arms for the fine tunimh part.
:hijacked: (sorry Splnkr) I tried to center the wheels in the wheel well and still have the pinion angle close but i think i fell short on the pinion angle. im assuming this is the problem as almost every time i start from a dead stop the ass end feels like it bounces up and down a little bit, violently if im not careful with the clutch. Is my goal to have all of the downward angle on the transfer case end of the (CV) drive shaft and to be within 1-2* on the axle end or do i have more of an allowance on the axle end?
 

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I left my MML in . Its sounds like you are still a little unsure but if you are then do it as you just said it just takes longer but its more fool proof . Like I said I started out with 17 as many do and adjusted it from their with no problems .
 

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:hijacked: (sorry Splnkr) I tried to center the wheels in the wheel well and still have the pinion angle close but i think i fell short on the pinion angle. im assuming this is the problem as almost every time i start from a dead stop the ass end feels like it bounces up and down a little bit, violently if im not careful with the clutch. Is my goal to have all of the downward angle on the transfer case end of the (CV) drive shaft and to be within 1-2* on the axle end or do i have more of an allowance on the axle end?
If things work out right you pretty much adjust your lower arms to get the wheelbase right and the uppers to get the pinion 1 degree less than your drive shaft angle. Some times you may have to re adjust the lowers depending on how much wou have to rotate the rear to get the pinion angle right but not much .You can almost eyeball the pinion angle to get it pretty darn close .
 

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Boy, this is a conundrum! Thanks for the replies. Lots of stuff to study. 15* really? That just seems so (too) steep. Again, when I measured from the end of the tcase to the center of my existing axle, I get 7*. So, if I set at say 15* with adjustable control arms (x4), I can still dial it in without having to worry too much about the angle of the spring perches? CG
 

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so what pinion angle did you end up using for your 8.8
I have an 8.8 swap with a ucf tummy tuck ultra high skid. ive done everything right except my brackets were welded at 17 deg which was way too high. im wondering if around 13 was the better number
 
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