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Unread 09-20-2013, 09:07 AM   #1
austinphe
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YJ- how much should you drop your transfer case

hey i am just trying to figure out whether i have to drop my transfer case at all with the 1" shackle lift i did on my yj, and what the ratio is when u raise your jeep. by that i mean how much do you have to drop the transfer case per 1" of lift on the suspension? and what else is required to change/modify when you lift a jeep and why? any info is much appreciated!

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Unread 09-20-2013, 09:14 AM   #2
Anticanman
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First of all, every jeep is different. A 1" shackle lift shouldn't necessitate a transfer case drop at all. Usually somewhere between 3 and 5 inches there will be sufficient vibration that will require the use if a transfer case drop or even better: a SYE and DC driveshaft.
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Unread 09-20-2013, 09:15 AM   #3
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I had a 1" shackle lift on my YJ. No such vibrations. If you get vibrations from a 1" shackle lift, then you might have some big issues to deal with...

And I'd never drop the t-case when lifting a Jeep, that pretty much defeats the entire purpose of the lift in the first place..
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Unread 09-20-2013, 09:18 AM   #4
austinphe
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I dont have any vibrations, but i just dont know anything about what goes into raising a jeep. so if you get a 3-5" you can either drop the case with w/e spacers come with the kit or you can put a longer driveshaft in?
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Unread 09-20-2013, 09:48 AM   #5
jokerchief462
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Correct

Here is what your driveline or pinion angle should look like.
tomwoods1.gif  
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Unread 09-20-2013, 09:48 AM   #6
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The axle pinion angle and transfer case angle should match on the stock rear drive line setup. When you lift the jeep say 4 inches, the transfer case is raised above the rear axle. Even though the angles theoretically still match, the drive line angle is increased and the ds is shortened, often causing bad drive line vibrations/excessive u-joint wear. Dropping the transfer case, reduces total drive line angle, reducing or eliminating vibrations and reducing u-joint wear.

If your shackle lift completely changes the pinion angle of your axle, you may need to compensate for that, but the only way to tell for sure is by installing the shackles. If you get vibrations, you have a few options. I would personally recommend a SYE since that is one of the best methods to cure driveline vibrations. It also allows the pinion and transfer case to have mismatched angles (to a point)

Check this link for more info an pics... http://4xshaft.com/CJ.asp
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Unread 09-20-2013, 09:49 AM   #7
Reno72
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Quote:
Originally Posted by austinphe View Post
I dont have any vibrations, but i just dont know anything about what goes into raising a jeep. so if you get a 3-5" you can either drop the case with w/e spacers come with the kit or you can put a longer driveshaft in?
Yes, but putting a longer DS in means a SYE. Some lifts over about 3 to 4" will still have vibration with a TC drop and require a SYE and CV driveshaft.
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Unread 09-20-2013, 10:17 AM   #8
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The biggest problem is the shorter drive shaft. Even with a slip yoke you can end up without enough length to keep the shaft in the seal and on the output shaft. On the street no problem but when flexed on the trail it may come off or be stressed enough to break.

The brake lines can be moved a little at the front Anitcanman has a great picture how he did it. You will have to jack your rig and check droop on the fronts and rears to see the impact.
broken-slip-yoke.jpg

sye3.jpg

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Unread 09-20-2013, 02:34 PM   #9
billy_butler
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i have also seen cases where the T-case rubs against the skid plate when you do a T-case drop. i would not imagine a 1 inch lift would cause any vibes or problems.
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