Yeah, you might get lucky. My exhaust needed serious modification. However, I also lifted the TC about 3".
4.0, 42RLE, NP241OR High Speed Vibrations After Re-Gear to 4.88 or Deeper
- Thread starter Mr. Bills
- Start date
Yeah, you might get lucky. My exhaust needed serious modification. However, I also lifted the TC about 3".
Looks like it's just going off the audio (noise) input, and matching the underlying frequencies of the audio with the expected RPMs of the various components. That's why he has to enter in the axle gear ratio, transfer case ratio and transmission gear ratios. Also, you'd expect some noise at the frequencies of the pistons and valves (i.e. multiples of engine RPM), which is why he's entering the number of cylinders.
So, yeah, it's just a fancy calculator. But I guess it can measure those audio frequencies from the mic without any sensors other than speed and engine RPM, which it seems like it gets from an OBDII adapter.
If that's all it's doing, you can probably do just as well with your ears and butt dyno if you're paying attention. And it seems unlikely that it would diagnose vibrations from belt driven engine components that are running at a ratio off of engine RPM.
If you wanted to do the same analysis by hand, you could record some audio of the vibrations at a set speed and RPM, then put it through some spectral analysis software to see if you can pinpoint vibrations at the harmonics of the relevant components. OK. Lots of math. But you could do that for free.
There are skid plates that claim you don't need a body lift.
The X I previously owned had a hybrid lift consisting of JKUR rear springs and OME JK front springs, and the JKUR shocks, modified to work on the TJ. The only other modification it had was bumpers and a Savvy TC shifter cable. It's 42RLE had considerably more miles on it, though, 156k+, and I attributed it's issues partly to that also..
I have sent a note to Dave asking his thoughts about the post I shared earlier, and whether a different skid plate would work in my case atleast. Let's see what he has to say. @Chris mentioned that he had the stock skid, 4.88 gears, and 4" of lift on this prev black TJ '05 Rubicon (33" tires?) and there were no vibration issues whatsoever on that rig. I am still completely unclear on why some Jeeps are absolutely fine and why some show the vibration issue.
I'll put it this way... there are more Wranglers that do not have vibrations after gear installs / bigger tires than there is Wranglers who do have vibrations. But, being the internet, you only hear about the bad stuff.
Now as for why this happens to some of them and not others, I'd like to know just as much as you guys. I'm rooting for @psrivats or @bobthetj03 to figure this out, because the solution may help people for decades to come!
Now as for why this happens to some of them and not others, I'd like to know just as much as you guys. I'm rooting for @psrivats or @bobthetj03 to figure this out, because the solution may help people for decades to come!
OP
I am pleased to report that the hub conversion has been completed without complication and the vibrations that commenced after my re-gear to 5.36 are now completely gone.
See this thread: https://wranglertjforum.com/threads/install-report-yukon-ya-wu-08-manual-hub-conversion-kit-and-vanco-16”-big-brake-kit.18025/
See this thread: https://wranglertjforum.com/threads/install-report-yukon-ya-wu-08-manual-hub-conversion-kit-and-vanco-16”-big-brake-kit.18025/
White Shadow 99
Member
Did you stick with 4.5 on 5 or go to 5 on 5? I believe your front hubs and u joints are now weaker if you did not upsize to the 5 on 5. Congrats though, I still have the drown on my LJ
White Shadow 99
Member
FYI I just helped my buddy buy a local LJ w/42rle. I test drove 3, 2 of the 3 did not have our issue all auto....still a mystery...
My build 4” currie, 1.25” BL, UCF alum. Tummy tuck w/alum engine skid, 5.13 gears, ARBs, new stock transfer case mount, everything new with SYE and both CV driveshafts rebalanced. MML did not make a difference. Played with pinion angles for a year. Remove F driveshaft and all good. When I take mine to JEEP West for R shock outboard and perch relocation see what Dave can do.
My build 4” currie, 1.25” BL, UCF alum. Tummy tuck w/alum engine skid, 5.13 gears, ARBs, new stock transfer case mount, everything new with SYE and both CV driveshafts rebalanced. MML did not make a difference. Played with pinion angles for a year. Remove F driveshaft and all good. When I take mine to JEEP West for R shock outboard and perch relocation see what Dave can do.
OP
If you read the thread that I linked you will see that I used the Yukon YA-WU-08 manual hub conversion kit that requires a change from the factory TJ unit bearings and 5x4.5" lug pattern to a spindle with Timken bearings and hub with the CJ-style 5x5.5 lug pattern. The kit uses 5-760x axle u-joints and the inner and outer axle shafts are 4340 chromoly steel. The steering knuckles included with the Vanco 16" Big Brake Kit from blackmagicbrakes.com are also more substantial than the factory TJ parts. Everything is stronger than stock.
@psrivats was able to improve his a bunch with some added sound deadening to the inside of the tub. He had Dave add the Noico 80 mil, then the 170 mil on top of that. It's a mystery how that helped, but he said it's a ton better. Mine improved when I changed to a Barnes 1/4" thick skid and sent my front ds to Tom Woods for a better balance. Sadly, I still get that pesky harmonic at 50-60 mph.
Have you considered locking hubs? If I could get my jeep to be completely vibe free without front ds, I will get manual hubs and be done with this. The only thing that's helped me so far is (1) thicker/heavier tcase skid (from UCF) and (2) LOTS of sound dampening (80mil Noico + 170 mil Noico). Nothing else has worked and Dave Kishpaugh has been breaking his head over it for 3+ months and below is some of what has been tried so far. The vibes were so damn bad after the regear as @Chris saw it when we drove it together. The Noico 80mil by itself did nothing, but when the 170 mil was added things got a LOT better and even Dave was surprised. The vibes are still not fully gone but they are more tolerable than before. I am still contemplating going back to 4.10s.
new crankcase damper - did nothing
pinion angles have been checked and rechecked and rechecked - no effect
front and rear driveshafts balanced 2x (2nd time was high speed balance) - no effect
new ujoints - no effect
axle shaft (have new chromoly ones) checked - no effect
new injector o-rings - no effect
We can get the vibration to go worse by installing a cut up stock skid and we could modulate the intensity with a heavier skid. I get vibes with just either front and rear driveshafts. Wish mine were the case where the vibes went away with the front removed.
This might be a dumb question, but what happens if you remove both driveshafts and run it up to what would be vibration speed? (Is that even possible with an automatic?). This vibration stuff is way way above my pay grade. I'm just a little curious.
@Mike_H suggested something similar. Take it up to speed and then drop tcase in neutral. I asked Dave to try it but I don't think this was tried on my jeep.
Someone who actually has the time to test these things really ought to. Dave for some reason was reluctant to do half the tests on Sri's list. It could have been very telling if he had.
Might not be a bad idea. I'd maybe try both and see how it turns out. It may be telling about where your vibration is coming from.
This might be completely off base, but are there any 2004 owners that have this problem currently? Just hazarding a complete guess here because Jerry says he doesn't have any vibrations and he has a 2004. You and Chris both have a 2005's. Was something changed between 2004 and 2005 at all?
That work looks so professional , I would love to see the entire Jeep . Love the wheels too.