i have a 96 zj with a 3.5 inch lift from rough country and im running 31's and on the website it say you may have to replace the cv joint on the front driveshaft if vibrations happen. my question is should i get an aftermarket front drive shaft or just get another cv front driveshaft. or could i just rebuild the cv joint and be fine. im new to the whole jeep thing and this is my first truck and first build. so sorry about my lack of knowledge lol
They say to not use the CV DS because it will blow the CV joint up. IIRC, someone makes a conversion yoke so you don't even need to swap the yoke on the T-case. You will need to upgrade to a ujoint DS. Some people's CV DS lasts 5 ft, some last 50 miles.
Carolina Drive line sells the adapter but they do not guarantee that it will not have vibrations. Your best bet would be to do it right and swap a u jointed yoke and shaft in. IMO using the adapter just adds more stuff the can go wrong when you could have just done what is known to work the first time.
Are there any zjs that came with a u joint shaft already? Or any kind of jeep? I'm going to be putting on my IRO 4.5 lift with all 8 adj. arms pretty soon and have been thinking if I might need to change my front ds but anyway I asked to see if maybe I could go to the junkyard and pull one off another jeep or whatever. But if there is another jeep that has one, what might fit with my 249 tc
I talked with IRO and they said addressing the front CV wouldn't be necessary for a 3.5 inch lift.
"The 3.5” kit does not require a t-case drop in order to eliminate vibrations in the driveline. The rear drive shaft can handle the increased angle just fine, If you have a CV style drive shaft you may choose to convert it over to a double cardan style drive shaft but it is not entirely necessary. You can do this by simply going to a junk yard and grabbing a shaft from a jeep that has the double cardan style driveshaft, you will need to yoke also. Or we have a conversion kit that is available with yokes and a custom made drive shaft.
All too many times people have bad ball joints, tie rod ends, control arms bushings and don’t address those issues before installing their lift kit and end up with death wobble then blame it on the lift kit."
Well I think it depends on the Jeep, age of components, etc. Just like anything else when lifting or upgrading the ZJ. My CV driveshaft lasted for 2 years on my 2" lift and 1 year on my IRO 3.5" lift with no issues. And yes I do more than mall crawl and off road with light to medium trails... no rock crawling but more expedition style of wheeling. I only changed it to a u-joint DS because of my 242 TC swap. I now have a slight shimmy on my steering wheel at 65mph where I did not with the CV shaft. And yes the DS was newly balanced, IRO adjustable control were used to set my pinion and caster with full alignment done at trusted Off Road Shop here in town.
I buddy of mine has a 95 ZJ with 5.2, 249 TC with a 2" lift and his CV shaft lasted 4 years under his Jeep with medium to light trails with a sprinkle of rocks crawling and did just fine. He only grenaded it when he was on a level 5 trail (I think he had no business being there) doing a gnarly hill climb. My opinion was it would of blow up with a stock u-joint DS with what he was doing... he did a 231 TC swap to a u-joint DS after the experience because he had to remove the front DS to limp home and toasted his 249. No vibes on his rig at any speed with his front u-joint shaft.
Another friend of mine had a 93 ZJ with a 5.2, 249 TC with a 5.5 in lift on stock arms with a CV shaft and that thing was unstoppable on level 5 trails keeping up with rock buggies, albeit with lots of crunched sheet metal. The only thing that finally killed the beast was hydro-locking the motor when misjudging the depth of a water hole. So as you can see his stock CV shaft lasted fine for over 225k miles...
So I say again, it depends... now I will say it is my feeling running a CV driveshaft the risks is only "slightly" higher.. I don't agree with the "it will explode and puppies will die" mentality of using a CV shaft on lifted ZJs. Sometimes I think I should have kept the CV shaft because of my 65mph shimmy but I know keeping things simple was ultimately better in the long run (u-joints are easier to change on a trail versus dealing with a CV shaft). I say run the CV shaft until or "if it does" break... then swap to a u-joint shaft.