Bigger Driveshaft?

extremeYJ · #1 (**permalink**) 07-20-2003, 08:00 PM

i was having this disscussion with some of my friends and it was about if you will need to do anything to your rear driveshaft on a YJ, such as get it lengthened or replace it with a CV drive shaft if you install a 4in suspension lift? anyone who has done a 4in lift on their jeep i would greatly appreicate your imput. thanks.[addsig]

Jeepr89 · #2 (**permalink**) 07-20-2003, 08:00 PM

Yes you will need to replace it. The best waya to go about it is to get a SYE kit to install on the t-case and then get a C.V. drive shaft. Just a couple weeks ago we did this on my friends 90 YJ. The t-case is easy to get out. and then we took it to a friend of mine to have him install the SYE kit and then we called a place here in town to make up a drive shaft. He drove around for over a year without doing this and he finally broke his driveshaft, rear housing on his t-case and the yoke on the rear diff. [img]modules/phpBB_14/images/smiles/icon_cry.gif[/img] [addsig]

Jeepr89 · #3 (**permalink**) 07-20-2003, 08:00 PM

Yes you will need to replace it. The best waya to go about it is to get a SYE kit to install on the t-case and then get a C.V. drive shaft. Just a couple weeks ago we did this on my friends 90 YJ. The t-case is easy to get out. and then we took it to a friend of mine to have him install the SYE kit and then we called a place here in town to make up a drive shaft. He drove around for over a year without doing this and he finally broke his driveshaft, rear housing on his t-case and the yoke on the rear diff. [img]modules/phpBB_14/images/smiles/icon_cry.gif[/img] [addsig]

Bounty__Hunter · #4 (**permalink**) 07-20-2003, 08:00 PM

No, you don't NEED to. You can get by with a transfer case drop kit, but it's not the right way to do it. Jeepr89 mentioned the correct way to address the rear driveshaft when lifting 4", a SYE and CV drivehsaft.

The TC drop will negate most vibes and will get you by until you can afford the expensive SYE and CV driveshaft. The TC drop does cost you a little ground clearance, which goes against why you installed a lift in the first place.[addsig]

Natty · #5 (**permalink**) 07-20-2003, 08:00 PM

Anything worth doing is worth doing right. Bounty is correct that you don't need to exchange driveshafts...but if you want to do it right - get the SYE and CV shaft. Ran mine both ways...when we first put on the 4.5" RE lift ('94 YJ), we kinda ran out of time on the weekend (not due to the complexity of installation, just the perpetuation of procrastination) and just threw on the tcase lowering kit. It still had some vibration with that on so the next weekend we installed the SYE and CV shaft. Awesome difference. Now has no vibration and rides smooth. Due to the pinion angle, I decided to leave the tcase lowering kit on there along with the SYE. Helps out under hard flexing. I know it takes away from the ground clearance...but if you're not in competition...don't worry. One inch difference on the lowering is a small sacrifice with 4.5" of lift. I'd rather have optimal drive line angles than taking a chance on breaking something $$$$. But it's weird that every Jeep is different - so just see what works.[addsig]

rwellman · #6 (**permalink**) 07-20-2003, 08:00 PM

What about the front driveshaft? What mods are best done with a 4" lift. I'm also planning on putting the 4" RE lift soon.[addsig]

extremeYJ · #7 (**permalink**) 07-20-2003, 08:00 PM

thanks for the information, i was right, i told my friends that if you wanted to do it right you would need to replace the CV driveshaft and a SYE, but they didnt believe me - thanks again[addsig]

Natty · #8 (**permalink**) 07-20-2003, 08:00 PM

The front should be fine, since it is longer than the rear. Less change in driveline angle. I didn't have to change out mine.[addsig]