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Discussion Starter · #1 ·
I've got this posted in the Ford Forum, but figured this might get more traffic. Got some issues with building a new rear driveline. Got my pinion angles and such and about 2x as much on my pinion as I am on the transfer case. To run a cv don't you have to have the same deg on both the transfer case and pinion in order to get proper cancellation amounts? Or would it be fine to run? Also, would a cv shaft be needed? I came up with 6deg of operating angle on the u joints (someone may want to double check me on my cal, I'm not 100% sure of this) But would it be possible to run a standard drive shaft? I could shim the pinion back down closer to the t case output, but that would drastically increase my operating angles and I would have to go with a cv, our would dropping the tranny and t case 1/2" to an 1' be the better solution? Here is part of the prev post with the numbers. Let me know what you guys think, thanks!

So this is what I've got goin on now. Rear driveline. 23.5" in length with an 8.25" drop. Here are my pinion angles. Give me some opinions and what you guys think I should/need to do.

Transfer Case Angle




Pinion angle.


 

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If you run a CV dline...You want your rear end pointed at the tcase -3*. (the -3* is to keep the lower ujoint working on the needle bearings. For vehicles that will drive at highway speeds, this is important to not prematurely wear out Ujoints)

If you run a standard dline, you want both angles to be at the same. If they operate less than 10* you "shouldnt" have any dline vibes.


To figure out the angles, here is what you need to do. If you dont have a dline, cut a piece of tubing to go in its place. Figure out the degree of what the dline would be at.

Say its at 20*. Measure your tcase output, is it an up angle or down angle? Most are about 5* down(towards the rear). So that makes the operating angle of the Ujoint 15*.
The rear looks to be 12* +, so that leaves the ujoint 8* of operation.

Will that senario vibrate, yes it should. In that senario I would put a CV dline in there and rotate the rear up an additional 3-4* (remember when you rotate the pinion up, the dline angle is going to change).

Hope this helps swiss...
 

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Yeah, what Shane said. I'm running around 18" of rear driveline in my cj5, with about 5" of lift and no t-case drop. It is a CV on the t-case and a single u-joint on the pinion end. The pinion is pointed almost directly at the t-case and I have no vibes up to as fast as I am brave enough to take that rolling death trap (had it over 90mph a few times).
I have been driving it this way for about 5yrs now and I did lose the rear u-joint once. That was due to off-road damage that lead to premature bearing failure.It also may help me to move the pinion angle so it is not quite as well aligned, but I'm lazy so it will stay the way it is for a while.
 

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Discussion Starter · #4 ·
Appreciate the quick responses. So you guys are sayng to shim the pinion UP another 3-4 deg? increasing the angle from around 12 to 15? In my mind that doesn't make sense, or should I be shimming it DOWN to about 9 deg? I really appreciate all the help.
 

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Yeah Swiss, Shane is giving you a CV scenario. Probably your best option given that you do drive it on road a lot. By raising the rear up so it nearly points at the Tcase you just slap in a CV at the Tcase and you are done.:deal: . Cost more but should run smooth. You would have to lower your axle a lot to get it down far enough to match the current Tcase angle. You could try raising the back of your Tcase up if you have room. that might get it closer so you could shim the rest of it out. But that would increase your overall Dline angle and might hinder your overall goal.

My front Dline is not right. the axle end is pointed up right at the Tcase but the Tcase is tipped down with a lowering block giving it at least 8* working angle. I can't run over 30mph with the hubs in or it will rattle the straps off the yoke at the Tcase. My fix is simple, just a CV at the upper end but it cost enought that I haven't done it yet.:eek:

Have you checked your PM's lately Swiss? I have 2 there for you.
 

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That, and when you get on the gas, the pinion tries to climb, so it will be nice and straight in that case.

Rudezuk said:
If you run a CV dline...You want your rear end pointed at the tcase -3*. (the -3* is to keep the lower ujoint working on the needle bearings. For vehicles that will drive at highway speeds, this is important to not prematurely wear out Ujoints)
 

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Discussion Starter · #7 ·
CV it is, now I've got to figure out parts to build one. I'll just need to bump my pinion up to the t case. (-3 or 4 deg.) Also, does it matter that the t case is down 5 deg? Or does it need to be at 0 deg drop?

Wildgoose said:
You could try raising the back of your Tcase up if you have room. that might get it closer so you could shim the rest of it out. But that would increase your overall Dline angle and might hinder your overall goal.
Is that what you were talking about Paul? if so, I believe I have enough room to raise it, question will be how. But I may be able to.

Thanks for all the help guys!

Side note: I've missed my pm's will check them asap and get back to you.
 

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If you are going with a CV (good idea) it won't matter what the upper angle is. You were sounding like you wanted to even out the angles so you could run regular u-joints. If you wanted to do that one approach would have been to raise the Tcase to increase the angle there closer to the one at the axle. With a lifted rig thats a real PIA to get all that stuff just right. When they build them at the factory they take all those angles into consideration but once you start lifting and changing axles it gets all screwed up. You will be glad you did the CV and I think your ford flat style yokes are probably easy to get hooked up to. CV in the rear of my jeep is built to mount to a flat flange.
 

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Discussion Starter · #9 ·
Another possible problem arose tonight. Any issues with running a driveline at this angle? This is something I completely overlooked and didn't plan on? Any big no no's to this situation?

 

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You'll prpbably have some vibes with that setup, and you're rear u-joint will not last as long as it should. Since it's already installed give it a test drive. If the vibes aren't too bad then just go wheelin.

A lot depends on how many highway miles this rig is going to see. if it's pimarily a trail machine then you're fine. If its a daily driver then you should pony up the dough for a dual CV. Jim's drivetrain in Boise could probably modify your new shaft with another CV joint on the pinion end.
 

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Swiss,

When I switched over to toyota axles, I had a noticable (but not unbearable) vibe from the driveline being offset to the side like that. Then I switched to a CV driveline, and the vibe was significantly reduced. Try it out. With a CV on one end you shouldn't have too much of a problem.
 

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Discussion Starter · #13 ·
Ok, sounds good. I've got a cv drivelien coming up. Just need to get some parts to get it done. This single u joint set up is to just get me mobile for now. THnaks for ll the help, I'll let you guys know how it turns out.
 
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