Outer Limits 4x4 Board

just installed a 5inch lift last weekend and i have a huge vibration coming through the rear tail shaft, yes it is flipped around,
what would this be, would it be the angle of the dangle in relation to the pinion, and would a set of adjustable trailing arms be on the order,

its on acceleration and deceleration and really really bad on the hioghway at 85-90kph

i would definitely say pinion angle as i had the same problem until i got adjustable trailing arms

check your uni-joints

did u have any vibration before the lift? is it a wagon or shorty? i stuck a 5 inch kit in my wagon the other day and have no vibs at all all standard arms and only castor plates in the front

check the condition of your unis, then try adjustable arms

the first thing i did when i took the shaft out was check the uni's, and they were all good

so im looking now for some adjustable upper trailing arms then


oh and its a lwb

why upper? why not lower? what are peoples thoughts on this?

i changed my lower ones because i wanted some more strength when im hitting them on rocks.

because if i pull the lower ones in to get the angle right it will look as though the front of the wheel is too far into the front of the gaurd,
with the upper ones i can push them backwards and keep the way the wheel sits in with the gaurd,

lowers will be after the uppers

when i extended my lower arms it shifted the diff back a little so its in the center again.
i still have the standard top arms

I have OME Competition 5" coils and no vibration. Tailshaft is flipped and the coil bases were resoldered after being rotated to match the new spring position.
Between the springs and the chasis mount there´s a rubber thing to isolate noise from the vibrating springs. Are yours still good? Try replacing these. Did that on mine and vibrations are gone...

I'm running longer lowers and standard uppers, wheel now sits centred, where before it would hit the guard while flexing

but if i run the lower ones and push them back/unwind them wont that push the pinion angle down further????? thats what i thought

outback_pootrol wrote:but if i run the lower ones and push them back/unwind them wont that push the pinion angle down further????? thats what i thought

Yep, that is what you want to do. The flange on the diff should be parallel to the flange in the transfercase output.

As MKPatrolGuy said, you actually need to increase the angle of the rear uni, so its as close as possible the that of the front uni.

Its when the 2 uni angles are at different angles that the vibration occurs, so if you legthen your uppers, it will worsen the vibes.

KIWI wrote:As MKPatrolGuy said, you actually need to increase the angle of the rear uni, so its as close as possible the that of the front uni.

Its when the 2 uni angles are at different angles that the vibration occurs, so if you legthen your uppers, it will worsen the vibes.

but if i lengthen the lower it will pull the pinion angle towards the ground????? is that what i want???????? it doesnt seem right to me


i am gonna try to space the crossmember down 12mm tomorrow as ive been told it will get rid of it,,,, sound good??

Shortie or longie? The guys are right you need to lower the pinion such that the flanges are parallel on the diff and transfere case, unis unlike C/V (Constant Velocity) cause a variation in the shaft speed relatant to the output flange, the angles on the front and rear unis need to be the same but reverse. Lowering the crossmember will help as will raising the front of the motor which you can do if you have a body lift and it dosent leave you dangly bits hanging lower. Unis dont transmit 100% power if you run them beyond 7 degrees causing vibrations also due to reflected power in the tailshaft if the rear uni is beyond 7 degrees. More angle is worse.

Joel

Just my 2 cents worth, I have a Guiii Lwb with 5" coils & 30mm spacers with drop boxes which spaces the cross member down 10mm. All the trailing arms are standard & running 35s with no rubbing at full flex. No vibration at all in 2wd at any speed but soon as I lock the front hubs in & get to about 60+kmh I get a small vibration from the front tail shaft. I put this down to the excessive angle of the front tail shaft. Same as the Swb's get at the back on big lifts. In saying this, my brother inlaws got the same lift but with no spacers & had all sorts of problems. Had to space the cross member down 20mm & get a cardinal joint put in the front tail shaft. But he still had no problems when in 2wd.