Driveline vibes after a couple weeks...

SO I have a 3.5 RE lift on my XJ, new leaf packs and coils.

No tcase drop on the NP 231

6* shims

SYE with front XJ driveshaft, rebuilt with all new u-joints.

Dana 35 rear

No vibes for a couple weeks, until the other day I was feeling confident and ran WOT from a stop just because I like the torque :roll:

Since then anything over an indicated 47 (on 31" BFG A/Ts) it starts to vibrate... increasingly worse as speeds go up.

any ideas?

Did you tighten everything up again? That would be my first guess.

Rear CV joint.

6º seems a lot for only a 3.5" lift, even a net 4" for the RE. Have you measured you DS angle to the diff angle?

Brendan_91XJ said:

6º seems a lot for only a 3.5" lift, even a net 4" for the RE. Have you measured you DS angle to the diff angle?

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it may be 4* shims, not 100%, one or the other... I'll have to find the shipping paper and see what shims I ordered from the offroad shop.

I didn't measure DS/diff angle...:twak:

i lifted mine 6.5" and use SYE and a modded front driveshaft. no shims and no vibes and why would you use any shims then? id say get them out and try again. i would avoid using shims much as possible, they sucks

95' heep said:

i lifted mine 6.5" and use SYE and a modded front driveshaft. no shims and no vibes and why would you use any shims then? id say get them out and try again. i would avoid using shims much as possible, they sucks

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I thought I could get away without doing DS work... guess not... lol... stock ds w/shims vibed pretty bad at 25-35mph and a ujoint died soon after, new front XJ DS was smooth until the other day... crap...

UPDATE:
tightened everything up a little as bolts were just a little loose... hmmm... I should use some locktite on more than the hack-n-tap center retaining bo

UPDATE: still vibes... ordered angle finder device.

You can pick one up cheap at Harbor Frieght, I think I paid 6 bucks for mine

Brendan_91XJ said:

You can pick one up cheap at Harbor Frieght, I think I paid 6 bucks for mine

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I got the same exact thing, about 8 bucks shipped off ebay, probably some guy bought a bunch on sale from HF and is selling them lol. Cheaper than me paying fuel to drive there and 6 bucks purchase price.

RCP- how can it be a rear cv? They're only a couple weeks old :wierd: on the other hand it makes sense for it to go bad right after running wot (if only once, from stop-45ish... pos ujoints!).

Vibes got worse, and worse, and after taking a turn (which I did immdiately before my wot run which caused initial vibes)

I felt a ujoint failure immenent, a clunk clunk clunk even at low speeds (idle in drive puttering along) and it feels like its coming from up front...

Pull your front shaft and drive it. if it still vibes, put the front back in and pull your rear, just drive it in 4. Process of elimination (done it tons of times before). Also, pull your front tires and brakes to check those u joints, if they're flopsy maybe time for an upgrade! I always use a failure to justify my upgrades... Part of why i'm broke all the time haha.

a reasonable checklist for driveline related vibes:
(cheap and easy, these can be done kinda all at once)
1. check all bolts in the drivetrain and suspension, check u joints , tre's and bushings. its free and easy, also check driveline angles as well. 6* sounds like way too much for a 3.5" but you never know until you measure. repalce any worn parts. dont over tighten DS bolts either.
make sure your rear pinion is 0-2* below the DS angle.
1.5 check tranny and motor mounts too while youre there.
2. check your alignment to make sure its in the ball park, tape measure and buddy make this quick to ballpark it.
3. make sure your tires are balanced, they can get outta balance pretty fast, like 2000 miles if your alignment is off, wheel hard, etc
4. pull front driveshaft then drive it freeway speeds(speeds of vibes).
5. if a sye, put front back on and pull rear ds then drive it up to freeway speeds. (maybe not if front is fully locked or welded though)
6. also check bearings, 3 bolts that hold unit bearings in, all steering ,( especially trackbar)
7. after seeing from the WOT from stop maybe you toasted a u joint??? especailly if they were overtoqued???? or at least made some other worn component more worn out now.
8. have DS shop double check DS's for balance maybe if youve checked all the above and know all of that is in order.

It's front u-joint. Pass side is about dead, drivers side has just a lil play. If anyone is bored feel free to post links to dana 30 ujoint replacement. I'm looking some up, but if you find one with some good hints and advice, be sure to let me know! Ditto if you have experience with this!
-Matt

http://www.naxja.org/forum/showthread.php?t=985628 is actually about replacing the seals, but if you stop following these directions right after getting the shafts out, then swap the U-joints as usual and put them back in, you have a writeup about replacing d30 U-joints.

I'm thinking with 210k miles on it I should replace the hub/bearings while I'm at it... Just Emptying Every Pocket... it's true lol!

I go the opposite way... I don't replace something "while I'm at it" unless it is a real pain to get at or its failure could cost me a lot of money. Once you've cracked the hubs/unit bearings out of the knuckles once, they should come out pretty easily the second time if you need to do bearings later, especially if you make good use of antiseize when putting it back together.

For right now to save $$ I'll run the 'ol hub/bearing assemblies.... gosh rusted bolts are a pain in the ass! heat and PB blaster to the rescue, and a big ol cheater bar!