Originally Posted by Closer
OK You're the only one that has said this so is there anyway I can verify this?
Yeah, I'll verify it for you, LOL. Seriously though, here is what happened. I had a Teraflex 2.5" long arm suspension lift installed on my 2010 JK. At the same time I had 5.38:1 gears installed, and 35" tires. When I got the Jeep back from the shop it had a driveline vibration at 70 to 80 mph.
Took it back to the shop to adjust driveline angles with the adjustable control arms -- made no difference. I had Tom Woods driveshafts on the Jeep, and we sent them back to Tom Wood to have them rebalanced -- made no difference. Had a local driveshaft shop check the shafts -- made no difference. Rebalanced 35" tires -- made no difference. Changed to a different set of 35" tires -- made no difference. Removed the front driveshaft and drove with just the rear driveshaft -- significantly better, but still vibrated. Removed the rear driveshaft and drove with just the front driveshaft -- better, but still vibrated. Had a new front driveshaft built -- made no difference. Removed both driveshafts and got towed down the freeway at 80 mph -- smooth as silk. Replaced both aftermarket driveshafts with the stock driveshafts again -- vibration gone.
This was a several month process, and the angles on the pinion / driveshaft had been adjusted literally hundreds of times trying to get the vibration to go away, and never got it to resolve. It did not appear to ba an angle problem. I think it may have been a yoke problem. The stock driveshaft yokes are "hub centric", and aftermarket yokes are not.
I can't say why the aftermarket shafts caused so much vibration. I do know that the stock R Zeppa style CV joints are better at preventing vibration than the CV joint style used on aftermarket shafts; that is why Jeep uses them. But, they do not tolerate extreme angles. AEV has also had problems with aftermarket driveshafts causing driveline vibrations, and they now retain the stock shafts with lifts up to 4".
You need to be aware that you might
have vibration issues if you start modifying your Jeep. Most don't, but some do. My current Jeep doesn't have any problems, and it has the same Teraflex 2.5" springs as my last Jeep, but short control arms this time, so I could do the installation myself. I have done every single mod myself this time, and so far it has been perfect.
I recommend keeping suspension lift to just 2 1/2", and retaining the stock driveshafts. 2 1/2" of lift is enough for 35" tires with the stock flares, or 37" tires with flat fenders, and most people don't need more than a 37" tire.