So I have a 2000 tj with a Quadratec 2.5” lift kit on it. When I put on the lift there was a really bad vibration at first. So I then, after looking on multiple forums, I put a transfer case drop on. It was a 1/2 in plus a couple washers making it roughly 3/4”. It did help calm some of the vibration but didn’t completely eliminate it. So I decided buy both upper and lower adjustable control arms in the rear and remove the t-case drop. I set the pinion angle 1 degree lower than the transfercase output angle and yet the vibration was still there and it was worst, occurring while accelerating starting around 2500 rpm and continuing through out the rest of the rev range. Now, the weird thing is that while casual driving my passenger rear tire rolled over a mound of snow, and a loud popping noise was heard and the vibrations were completely gone. But then after another day of driving the vibrations came back. Another thing to note is that my rear axel is off center with the track bar relocation bracket installed with the kit. So, I don’t know if that could be the issue. Any help would be great.
Yet again another driveline vibration thread
- Thread starter Landon.B
- Start date
No, I didn't put a SYE on. Would that fix the vibration? Would I be able to re-install the t-case drop to temporarily fix it? or is a SYE my only option?
That's your issue then, 100%.
The only way rear adjustable control arms work is if you have a SYE and double cardan driveshaft.
You could reinstall your transfer case drop and get rid of the vibration, yes. But now that you have adjustable control arms, the former is the proper way to do it.
BTW, check this thread out:
What is a SYE/CV driveshaft and why do I want one?
More on Pinion Angle Alignment
So what about a transfer case drop or motor mount lift? Will that fix my driveline vibrations?
The answer is maybe...
The function of a transfer case drop is to make the output shaft of the transfer case parallel to the input shaft of the pinion - after a lift has been installed and the pinion sits further away from the frame. The pinion centerline and the output shaft centerline must be parallel for single cardan shafts with a slip yoke. A MML (motor mount lift) also functions to align the output shaft with the pinion centerline.
So why did I say maybe the t-case drop would fix vibes? - because when you lift a Jeep, the t-case drop or MML will only go so far to correct the pinion angles. The taller the lift and more flex you have, the closer you get to pulling the driveshaft completely off the t-case under flex. The best thing to do is a Double Cardan Driveshaft.
For single cardan shafts (stock shaft) - you want the u-joints to function at less than 3 degrees.
If you can't keep less than 3 degrees at ride height then you need a Double Cardan Driveshaft.
For double cardan shafts you want the pinion u-joint centerline to be between 0.5 degrees of zero of the output shaft centerline of t-case at ride height - adjustable upper control arms allow you to rotate the pinion.
You'll need to do the math for your application:
What is a SYE/CV driveshaft and why do I want one?
More on Pinion Angle Alignment
So what about a transfer case drop or motor mount lift? Will that fix my driveline vibrations?
The answer is maybe...
The function of a transfer case drop is to make the output shaft of the transfer case parallel to the input shaft of the pinion - after a lift has been installed and the pinion sits further away from the frame. The pinion centerline and the output shaft centerline must be parallel for single cardan shafts with a slip yoke. A MML (motor mount lift) also functions to align the output shaft with the pinion centerline.
So why did I say maybe the t-case drop would fix vibes? - because when you lift a Jeep, the t-case drop or MML will only go so far to correct the pinion angles. The taller the lift and more flex you have, the closer you get to pulling the driveshaft completely off the t-case under flex. The best thing to do is a Double Cardan Driveshaft.
For single cardan shafts (stock shaft) - you want the u-joints to function at less than 3 degrees.
If you can't keep less than 3 degrees at ride height then you need a Double Cardan Driveshaft.
For double cardan shafts you want the pinion u-joint centerline to be between 0.5 degrees of zero of the output shaft centerline of t-case at ride height - adjustable upper control arms allow you to rotate the pinion.
You'll need to do the math for your application:
With a double cardan driveshaft and SYE (plus your adjustable control arms) your rear pinion and driveshaft will look like this instead:
myNameIsMud
New Member
I have a 2000 Sport with a 5” lift. Does this angle look correct? I’m getting a steering wheel vibration only when accelerating and not when coasting. Didn’t start until I put new tires on. Only difference in tires was Mud Terrain to All Terrain.
I had a similar issue with my tj. From what I can tell your rear pinion is way to high. The pinion angle should be parallel with the output from the transfercase. I’d suggest, if you don’t have already, get adjustable control arms, or at least rear upper ones so you can adjust the pinion angle. When I tried to adjust my pinion angle it didn’t help the vibrations. So I had to get a sye kit and that got rid of the vibrations.
myNameIsMud
New Member
Thanks man, I’ve been reading up on the SYE. Did you do it yourself? It looks pretty involved and might be a bit over my head.
Yeah, I did it my self. It seems really intimidating at first, but I just watched a ton of YouTube videos on it and that really helped me build my confidence for it. Once I got to doing it my self it was actually really simple. My only suggestion is that if you do decide to do it buy some horse shoe snap ring pliers it will speed up the install immensely.
myNameIsMud
New Member
It's pretty easy and can go together 1 way for the most part. It took me 45 minutes or something like that my first time. As with most first time work, plan on not driving it the next day just in case you need extra time to put it together.
myNameIsMud
New Member
These are the pliers I used: https://www.amazon.com/gp/product/B00209ETSS/?tag=wranglerorg-20
JB Conversions sells the shortest SYE kit on the market. I have their SSSYE in my red LJ.
You're going to need fluid to fill the case, RTV, loctite, and if you need to remove the front yoke I suggest having a replacement seal on hand. Mopar part 4446487. Here's a picture of my old front yoke seal vs a new one:
myNameIsMud
New Member
Anyone still on here to post how this turned out? I have a 3" lift and getting driveline vibration.