At this point you just need to swap out that 4.0 for a Hemi and see if that solves your issues
Sure, throw more money at it and it'll go away, right? Lol!
New control arms (Savvy versus Metalcloak)
- Thread starter WNC05willys
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Sure, throw more money at it and it'll go away, right? Lol!
At that point, I'd buy a stock rig and swap parts until you have your old rig again vibe free (but maybe undergeared).
I've considered gearing up to 4.10's, and or going to larger tires to slow the DS down some. Tired of throwing money at it.
Exactly. Once all you have left is the tub, the vibration will have to be gone by then
I understand, I've been fighting intermittent stalling for a few years off and on. If there was another vehicle that could do what I want to do with this, it would already be in my garage.
I have on occasion mentioned that. I have on every occasion been soundly told I was full of shit.
Theoretically, you should be able to tune out the vibrations caused by axle wrap out via pushing the pinion angle down when static, no? Then when you hit the highway the axle wrap and lowered pinion angle counteract each other to create the correct angle. The whole theory seems like a bit of a stretch to me. That might be an easy test? Obviously you wouldn't want to leave it that way long term.
It seems a lot would depend on how wide the range of deflection is compared to the pinion's range between vibes and no vibes
Quite possible. Here is what I do know for certain. The rear pinion is very unforgiving when it is set high. Under load, the lowers are in tension, the uppers are in compression. That is the exact direction one would move them to raise the pinion. Shorten the lowers, lengthen the uppers. If you have a sensitive rig, you don't want that happening and then the challenge becomes to find the angle that doesn't vibe when it is low enough at slow speed to not rise past the sweet spot when the load comes on. A lot of folks also don't understand that a vehicle with the aerodynamics of a brick uses a lot of horsepower to just maintain speed and that is a higher load on the arms. Higher load is more potential for displacement.Movement is movement. But it's been ruled out, so maybe we are.
You are correct but if you get it too low in order to combat the rise in pinion angle, that will cause vibes as well.
Would take more effort to quantify the problem. A camera pointed at an angle finder on the pinion would do it, but that isn't the easiest thing to do. On the highway at cruising speed, I'd imagine axle wrap is pretty close to 0? If axle wrap was the main cause of vibes, maybe the easier test is to see if the vibes get worse under acceleration. My pinion angle looks low to my eye, but if I put my foot down in third at high speed I get a slight vibration.
How much axle wrap do you perceive there to be when coasting down hill on the freeway at 70 mph in neutral?
Is it the same conditions that create vibes when the axle is under load? The pertinent details are to know the range of deflection at the pinion compared to the range in which the pinon is happy.
On yours, is the pinon ever happy?
If the vibes go away when you get off the pedal or put the Jeep in neutral, then fine. But I'm not sure I've ever heard of a vibe that had that specific characteristic. The axle wrap would have to be extremely severe to get the pinion in and out of its "happy range" dependent on load. I'm not finding this too convincing.
Either way, I would think it would be counter productive to use components that allow unnecessary axle wrap, especially on a sensitive vehicle.
Can't disagree with that. Would be interesting to actually get a video of a JJ vs a MC joint for the rear arms on acceleration. Not the easiest thing to pull off since most people only have one set of arms.
No, it is never happy, and I have adjusted it in 1* increments followed by a test drive, from 3* higher than pinion to 5* lower than pinion* with no change in severity. I've also changed control arms from Currie to OEM, to MC.
In my case, the vibes are speed related. I can jamb thru the gears hard from 1st thru 4th and it is smooth as butter. Get up to 55mph crusing speed, up hill, down hill, straight level, coasting out of gear, it doesn't matter. The vibes start to kick in at 55mph and get a bit worse at 65mph on up. I've also tested it with the rear axle on jack stands so that just the rear is spinning and can duplicate the vibes. I've been thru 3 rear drive shafts in 2 years trying to find the rainbow unicorn of balanced drive shafts with no luck.