Just upgraded from a 2.5" lift and 35's to a 3.5" lift and 37's this past January. Put about 12K on the new setup and the stock drive shafts went out on me. Bought new Rough Country front and rear drive shafts and the mechanic popped them right in there in about an hour. When I test drove it around the block there was a pretty significant vibration when traveling at about 20mph that wasn't there before. The mechanic told me that I needed to get some adjustable upper control arms to fix the new drive shaft angle to fix the vibration. Just wondering if anyone else has experienced this as well. I didn't have any vibration issue with the stock drive shafts.

 

Yup you need Adj CA's to bring the pinion more in line with new shaft. With raising pinion you
Will be lowering the castor in front, try and shoot for 4* castor and 2* pinion. With double Cardin DS's
The pinion needs to be as much in line with shaft as possible . Not sure about the tranny prob....

 

Thanks @rebar ordered some earlier today.

 

The front isn't really too important, but the rear is. You want it pointing 1-2 degrees below 0 at the pinion.

 

I did not see a programmer/tuner in your specs list. Does the computer know what the new tire size is? (and gear ratio?) Haven't actually followed the posts on this, but pretty sure I saw some people posting similar issues - newer model jk's with taller tires and it being a programming issue.

Another question for the driveline vibes, what is the caster at now? I got lazy and had a shop install new arms for me recently. They set the caster up near 10 degrees, which gave nasty vibes around 15-20 mph as I drove around the building ... and right back to the front door.

 

Similar issues on my 14 sahara auto. 3 inch lift vibration from the rear on mine. did the tom woods shaft. at the pinion the shaft has to be pretty much straight on. tried 2 degrees up and down. works best straight on. had to do the upper adjustable arms. did the tuner for tire size and gear ratio.

 

The front is what people were blowing up from the vibrations, a few years ago.
The front of the T-Case was exploding when the angle between the front pinion and drive shaft was more than a couple degrees from straight, when they had installed an aftermarket drive shaft with a double cardan at the T-Case..

 

@invest2m4
Installed some Rough Country adjustable control arms today and solved the problem. Fingers crosses those nasty vibes don't come back.

@nthinuf
Yeah I just upgraded my profile, yes the cpu knows that I'm running 5:13's and 37's via my AEV Procal.

@beemerman
So I'm assuming you're not having any more issues? How many miles have you driven post fixing these issues?

 

Safe insurance

 

What's your caster angle after installing control arms?