Author Topic: Driveshaft vibration question  (Read 491 times)

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Offline stan98tj

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Driveshaft vibration question
« on: August 21, 2014, 07:42:50 PM »
Got a driveshaft vibe question.
Had to put a mount under my trany for my tummy tuck , now I get a slight-moderate vibration between 35-40mph after which it goes away.
I know I have to adjust pinion angle to correct it but for a multitude of reasons which may include the trac bar mount on the 8.8 being off by an inch or two, I can't adjust the arms to correct pinion.

Here's the asshat question: how bad is it to drive around like this? I have an SYE and double cardan joint.
98 TJ 35"Maxxis Trep.Old Man Emu 2.5""+1"BL,IronMan Fab control arms,4.56gears,Ford 8.8+ARB,Currie/IronMan steering, WARN VR10,HP D30 sleeved+ RCV,Body Armor Rock Rails WISHLIST:TDi.Girlfriend hates it :) If you can read this don't flip me over i dont have any $$ left to fix it

Offline sharpxmen

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Re: Driveshaft vibration question
« Reply #1 on: August 27, 2014, 04:37:00 AM »
how much is out? if not much and if you only get it at that speed then it's something else (resonance/harmonics) in my opinion - maybe the shaft is out of balance. A common problem is if you pulled the splines out and put them back in a different position, after that your balance might be off.
if you didn't do that and you're sure it is balanced I would try to rotate the CV (180 degree on the t/case yoke) and see if it changes the speed at which it does this.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline 95 Lowbuck

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Re: Driveshaft vibration question
« Reply #2 on: August 30, 2014, 08:57:16 AM »
if you didn't do that and you're sure it is balanced I would try to rotate the CV (180 degree on the t/case yoke) and see if it changes the speed at which it does this.

This works.
I have used an indicator to find the right combination of yoke to driveshaft combinations.
Would be surprised at the difference.
But you will have to address the driveline angle eventually as the u-joints will take a beating.
1995 YJ RioGrand, 2.5, AX5, 231 T.C., A.A. SYE,
D30, XJ D44, Truetracs F+R, CV D.S. F+R, 4.88's
R.E. 4" STD., 33-10.50 BFG KO2's on stock rims.

Offline stan98tj

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Re: Driveshaft vibration question
« Reply #3 on: August 31, 2014, 08:02:06 PM »
So I did have it pulled out all the way and had to put the shaft back together. It is possible i changed the position , however, it vibrated at 35-40 before I had the driveshaft out. Basically the vibe started after the mount was installed.
I drive it to Rausch Creek (4hrs away) and noticed the vibration comes back at about 60 depending if im accelerating up a grade or not.
98 TJ 35"Maxxis Trep.Old Man Emu 2.5""+1"BL,IronMan Fab control arms,4.56gears,Ford 8.8+ARB,Currie/IronMan steering, WARN VR10,HP D30 sleeved+ RCV,Body Armor Rock Rails WISHLIST:TDi.Girlfriend hates it :) If you can read this don't flip me over i dont have any $$ left to fix it