Vibration under load

Hooligan

Hooligan

New member
I have a vibration that can be felt in the gas pedal,steering wheel. Feels like its under drivers seat or front end of the jeep. It happens when i hit a bump..the vibration starts..i let off the gas and it goes away. Back on the gas and its still gone until the next bump. Cannot reproduce the vibration when coasting off gas only happens when on the pedal after bumps. Jku 3" lift. New drag link ball joints and coils. Any ideas ?
 
pvanweelden

pvanweelden

New member
I think I would start by eliminating some things- check the u joints in axle shafts, and front and rear shafts. usually a u joint will cause havoc regardless of speed, but if its in the early stage of going bad, it could be occasional like you described.
check tie rod ends- have some one turn the steering wheel from side to side, while you watch every tie rod end (4) to make sure one isn't moving in and out.
Check track bar bolts, lca, and uca bolts to make sure nothing is at all loose.
is it an auto or manual?
 
Hooligan

Hooligan

New member
Still not got round to removing the front ds. Got the skid plates off..too much snow to tackle the shaft right now. The 8mm bolts are so tight. Will blast with liquid wrench and get to it when the weather improves.
Question? I can rotate the front driveshaft back and forth enough to feel it in the front diff and ever so slighty in the axle u- joints. Is this normal. Rear shaft is solid and has zero play in it. Bit of a noob when it comes to solid axles and 4wd drive set ups.
Thx as always
 
JEEPnGEO

JEEPnGEO

New member
Might be a broken belt on one of your rear tires. When you step on the gas you are shifting pressure on the rear tires and if a steel belt has stretched or broke you may feel a wobble. Rotate the backs to the front and see if you still get the wobble.

?????

You didn't mention the speed of the vibration. If the vibration follows the speed that you are driving or is it 3 to 4 times faster than you are driving. The tire is large so the wobble issue would be noticeable and slow with every rotation.

Thought I would mention that before misplacing all four donuts.
 
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Canvas JK

Canvas JK

-
Try checking the torque on all your suspension parts. Also check your motor mounts and transmission mounts to be sure those are all in in tact and not broken.
 
Hooligan

Hooligan

New member
Rotated wheels no change. No play in wheels so presume bearings ok. Front wheels can spin somewhat. When wheels removed its hard to turn the brake rotor but believe thats normal.

The vibration is felt mostly in the gas pedal. No sound just a vibration which goes away if I let off the gas pedal.

New shocks
New springs 3" (was 4")
New ball joints
New drag link.
Lca drop brackets

Vibration has become gradually worse since changing the springs.:confused:
 
JayKay

JayKay

Caught the Bug
Pinion angle? When I used to have lowered trucks, you'd get a vibration under acceleration if the pinion angle wasn't correct after dropping the rear. This may not affect anything since you're still running the OE rear shaft.
 
904Jeep

904Jeep

New member
Hooligan said:
Lca drop brackets

Vibration has become gradually worse since changing the springs.:confused:
Click to expand...

The AEV drop brackets have three holes for positioning the lower control arms in based on lift height. When you changed coils did you change the the control arm position in the drop brackets for the lower lift amount. Could it be possible that the OP is over correcting the caster?
 
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Hooligan

Hooligan

New member
Wife says she can feel it in the passenger seat. She described it more as a clunking / something rubbing against the frame or suspension. To me it feels more like a vibration felt in the gas pedal and seat thats front end related almost like the coils are vibrating. Going to take apart the front suspension tomorrow and inspect.
 
Hooligan

Hooligan

New member
Loosened all control arms ,track bar and disconnected sway bar. Shook it out and then torqued to spec. No change. Had the wife turn the wheel while I checked the TRE's they all look good. Changed front diff fluid and rear diff fluid. No change.
Did find some metal pcs in the rear on the magnet.
1393174914370.jpg 1393174945285.jpg

I used spidey minifig so you can determin the size. I think this is a separate issue to the vibration issue.

Im thinking it may be the motor mounts. If I put the jeep in reverse with brake pressed the engine vibrates. Same if I put in drive and hold the brake. I cant see movement in the engine fom above. Underneath if I push up on the oil pan I can feel the engine move. Its not much, its like the rubber mount is flexing. Is this normal?

Next step is re-install front ds and remove rear ds.
 
C

CerOf

Member
Those are pretty big pieces of metal and not normal...that would be a bigger concern to me than chasing down your vibration...heck, it could be contributing or causing it.


Sent from a a few tin cans and some string.
 
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