Just finished installing a 4" lift on my tj. Rough country so it has nonadjustable control arms. Just took it out for a test and have bad driveline vibes. Looking at the pinion angle it looks as I need some adjustable rear uppers. I have a sye and rear dc driveshaft already installed. (and yes I did the pinion seal when I was down there lol)
Driveline vibes
- Thread starter Morks
- Start date
Angle doesn't look so good in the picture, I'd say you're onto someting.
Pinion is low. Adjustable CA’s are in order. Ideally do both upper and lower. If only one set, uppers.
I did the exact same thing a while back, 4" lift + SYE & new driveshaft, and ended up with bad vibes. It felt like it was in the wrong gear was the best way I could describe it. Added adjustable rear upper arms and got the angle dialed in, everything is perfect after that. It was the first time I had bought a lift kit, but I'll forever be amused whenever I see a kit say something like "you may need an SYE or adjustable arms" because there's no way you wouldn't need those things, imho. Or maybe it's just marketing to get you to buy their cheaper kit that doesn't have stuff you'll end up buying later.
Exactly, definitely a PITA but hopefully the first and last ever kit I buy until I can start making my own crap lol
edit... did you experience death wobble after your lift?
Set your toe to 1/16”-1/8” toe in. Center your steering wheel on the drag link. Fix your pinion. Then, start diagnosing DW. Start with a perfect tire balance. Check your Trackbar, especially at the axle end to make sure it’s not wallowed out so there’s play (have someone steer from 10-2 repeatedly while you watch for play). Then report back to the forum. Ball joints, tie rod ends, all kinds of things could be wrong, but don’t just throw Money at it. 99% of the time it’s a tire balance issue
Last edited:
Great post- tires typically set it off, but loose components can make it worse- and if it gets set off by a bump it is likely loose components more so than the tires- also check your control arm joints, especially the upper front passenger at the axle.
It can drive great, be persistent.
I have had ZERO issues post lift (post adjustable upper arms, that is). But I had also already replaced my ball joints, track bar, and ZJ steering swap, so things were already stacked in my favor. Death wobble can come from a ton of places.
Put the arms in, did an alignment, straightened out the wheel. Did not DW once but felt like it wanted to possibly, I also don't have my sway bars in right now so that could be the case I was definitely trying to get it to DW and felt like it wanted to start once... Going to put the zj steering conversion stuff in soon so hopefully, that'll tighten things up instead of the original crap.
Oh yeah, just didn't have a vice or anything to press the sleeves into the bushing nicely, done now though
Nucklenelson
Member
By any chance do you get vibes over 65
I have a 4 inch lift with the stock arms and my pinion angle looks identical to yours. It looks pretty good but I’m going to try to balance the tires first and see if it fixes it.
After getting arms, and doing an alignment I was good with death wobble and driveline vibes. The driveline vibes were 100% just the crappy pinion angle. I'd say just get the adjustable uppers and do it right and do it once.