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View Full Version : XJ vibes, cant go over 50mph



LouisianaZJ
09-18-2004, 01:09 AM
Problem: vibes after 50mph. I do not hear the vibes and the vibes are a strong firm shaking that can be felt throughout the jeep. It feels like it is coming from the rear shaft. I recently had to tighten up the rear pinion nut cause it was backing out, it is still tight. It started getting noticably worse after this, but i had vibes before this as well


Specs:
XJ
231, D44 rear
6" lift
tom woods SYE with CV shaft (both under 2yrs old)
no TC case drop or anything like that
recently balanced 33's
4-6* shims (not sure)

i know the driveshaft is like 16* and the back of the housing is about 16*-17* as well. Ideally it should be 14* or so...

Checked:
no ujoint play
no real tcase play, but there is some crazy black stuff coming out of the t-case (almost like black ink) but the t-case fluid is bright red from the fill plug. pic http://www.jeepsunlimited.com/forums/attachment.php?s=0feda56e3f3171a17fe8615fef463303& postid=4815879 its alot darker than in the pic that was when it first started
I was gonna call up tom woods about this cause Im scared it might be the t-case output bearing :shock: or something

I can move the the transmission up and down probably a total of 1" so the bushing is a little soft I guess, but kinda pricey to replace

I was also considering getting the rear shaft rebalanced and checked for straightness (how much should this cost? like 20 bucks?)

I could also try fooling with the pinion angle some more, but I gotta order new shims cause no one here sells them in stock that I can find anyway

robselina
09-18-2004, 10:09 AM
ballancing your d-shaft should be like $40.

I'd replace the tranny mount, that seems to be part of your issue

as for the 231, describe this black stuff and how much end play there is on the output shaft.....

LouisianaZJ
09-19-2004, 06:30 AM
minimal play on the output, actually no noticable movement but just enough to hear a sort of click moving it up and down

the black stuff is ATF consistency and has some grit to it (almost like powdered graphite) and it is straigh black not dark red. Previously it was just leaking ATF out of the seal, it started turning black after a wheelin trip

im gonna replace the trans mount this week.

Alaska ZJ
09-19-2004, 10:09 AM
to test out the d shaft balance you can clamp a hose clamp around it. Takes a bit of test and tune to get it right but you should be able to dial out the dshaft vibes.

LouisianaZJ
09-19-2004, 04:36 PM
http://img23.exs.cx/img23/4923/jeepxj_1523.jpg
pic of the stuff today
i noticed when I manually turned the shaft the seal would spin inside the housing and stayed stationary around the yoke, so im guessing it could actually be ground up black rubber + ATF I am seeing since the seal is supposed to work opposite way, stationary in the housing and the yoke spins around inside of it

as far as driveline angles, I took some measurements with my crappy little angle finder:

rear DS 15-16*
rear housing 18-19*

rear shims were unknown size, measured 1/2" x 1/8" x 5" long, which i determined to be arc tan (1/2"-1/8" / 5") = arc tan .075 = ~4* shims

the rear pinion should be a tad lower than the DS right, so if I took out the shims that should put me just about right? wouldn't it?

robselina
09-19-2004, 10:19 PM
yea, your seal is shot. I'd replace the seal and see what the hell happens there, and get the d-shaft ballanced......it's a start at least.....

LouisianaZJ
09-25-2004, 06:43 PM
update:

alright i was getting vibes at 50mph+ the vibes were strong vibes that felt like the were comin from the unibody trans crossmember. I could not go past 50mph

changed trans mount (old one was not totally shot, but not too firm) - helped reduce intensity of vibes

rebalanced tires (all were 5oz out of balance)- helped alot, can now push thru to 60mph, 40-50mph still gets some vibes

alignment- not much difference

6" with TW SYE + CV shaft (1yr old), pinion angle about 2* higher up than DS angle, 4*shim and shackles measure 7" (+3"??).

im putting in a new rear axle next week and I think i'll try taking out the shims when that goes in.

btw, I tried to get a new sael from tom turd, i mean woods and they would not give me a new one.

nate
10-26-2004, 02:07 PM
to test out the d shaft balance you can clamp a hose clamp around it. Takes a bit of test and tune to get it right but you should be able to dial out the dshaft vibes.

:D and everyone said my shit was ghetto with the 4 clamps to balance it.

OverkillZJ
10-26-2004, 03:13 PM
to test out the d shaft balance you can clamp a hose clamp around it. Takes a bit of test and tune to get it right but you should be able to dial out the dshaft vibes.

:D and everyone said my shit was ghetto with the 4 clamps to balance it.

Nate, your shit is ghetto if you LEFT the clamps on LOL


I've only done that to test if the shaft needed rebalanced, not as a permanent solution, haha

nate
11-02-2004, 02:34 PM
Oh, well the clamps are still there :D

The shaft is balanced. I think it's the RE hack and tap. I have an AA SYE to install someday.

LouisianaZJ
11-24-2004, 06:43 PM
update again.

i replaced the seal, :roll: TW would not send me a new one, so i RTVed it back in
the black stuff was ground up rubber seal material + ATF

i put in a new D44 rear, left the shims in. still have vibes....
so im guessing it must be
1- bad pinion angle
2- unbalanced shaft/ bad CV

JeepinHank
11-29-2004, 01:29 PM
How do your angles measure out? If you haven't done it yet, just get yourself one of those $10 angle finders from your local box store and check it out.

IIRC your pinion angle should be 2-3* higher than the angle of your output shaft at the t-case. The reasoning there is that under acceleration, your pinion angle will tend to rotate down wards. To be safe - Someone check me on that, cause I'm bad for mixing up the higher/lower and up/down parts.

That should at least get you started in narrowing it down.

LouisianaZJ
11-29-2004, 09:26 PM
pinion rotates up with accel.

i have an angle finder but it is hard to read. the yoke and d-shaft are withing 2-3 of each other, possibly pointed up a touch too high.

i have 4* shims i will be taking out

JeepinHank
11-30-2004, 12:58 PM
pinion rotates up with accel.

Figured I had it mixed up.

Sounds like your angles aren't out enough to be causing the vibes you're experiencing. That is if your measurements are close.

I'd hate to think its a bad/unbalanced driveshaft.

Are you sure its a driveline vibe? Have you looked at your motor mounts? Worked on a friends s-10 blazer a couple of weeks ago. He was having some driveline vibes, and I thought it was his pinion angle causing them. It wound up being a pass. side motor mount. After thinking about it, he'd gone through 2 driver side motor mounts, but never changed the pass. side. They don't seem to wear out as often, and are hard to diagnose when they do.

LouisianaZJ
12-15-2004, 08:53 PM
i ordered some MORE bombproof motormounts to see if that helps, still have to install them

i figured i would need them soon anyway with the extra torquiness of the 4.56 gears

i remeasured with a better angle. DS: 15.0*, yoke: 16.5*

im probably going to be putting in a 2* shim.

Jim311
12-16-2004, 12:36 AM
update:


btw, I tried to get a new sael from tom turd, i mean woods and they would not give me a new one.


Tom Woods is a douchebag. I'll be buying my shafts from High Angle Driveline from now on.

2drezq
02-08-2005, 01:03 PM
My son said his XJ "shook a little" & got worse at highway speed, HOLY CRAP! It shook so hard I thought it would leap off the road! I took it in and found:

1: RF tire FIFTEEN OUNCES OUT OF BALANCE!

2: three others needed balancing.

3: Said RF tire out of round.

4: Roofing nail in LR (Explains the slow leak I guess)

5: four different tire pressures.

Rebalanced & rotated tires-vast improvement.

OverkillZJ
02-08-2005, 02:59 PM
update:


btw, I tried to get a new sael from tom turd, i mean woods and they would not give me a new one.


Tom Woods is a douchebag. I'll be buying my shafts from High Angle Driveline from now on.

I get the impression I'm the only person who hasn't had problems with Tom at all. Hell, he rebuilt my shaft when it siezed up for next to nothing, and they had to cut the splines out.




But I'd go High Angle if I were to do it again ;)

nate
02-08-2005, 03:32 PM
Try balancing the shaft with hose clamps. My driveshaft is balanced, but I get BAD vibes at 65. I had to put 3 or 4 hose clamps to balance the entire assembly and the vibes are gone. I'm thinking it's an issue with my RE Hack and Tap... Dunno for sure though.

LouisianaZJ
02-13-2005, 12:13 AM
i put in differnt shims so the ds is a touch lower than the d/s

4.56 gears
replaced all trans and engine mounts

it now vibes at 65 mph

im thinking either ujoints or an out of balance dshaft or something?