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vibration...hopin' not driveline related

collegeoffroad

NAXJA Forum User
starts vibratin' around 25MPH, but only when I've got my foot on the gas. Clears up around 35/40, then comes back around 55MPH, only to disappear again at 65MPh

...hoping it's not driveline vibes, but what else could it be? Ball joints...wheel bearings?:dunno:
 
Check your motor and tranny mounts.
 
old_man said:
Check your motor and tranny mounts.

for a mechanical noobie...how?

I was also searching around and found this, which seems like it might be a possibility:

Steering Wheel Vibrates:
The steering wheel vibrates at speeds of 45 to 60 MPH. You will also notice that the car is vibrating or twitching down the road. This can be a very dangerous problem and should not be ignored. Sometimes the problem only occurs when the brakes are applied.
Possible causes:

1. Warped or damaged brake rotors and/or drums: Machine or replace brake rotors and/or brake drums.
2. Loose wheel lug nuts: Tighten wheel lug nuts to specification.
3. Out-of-balance wheel and tire assemblies: Balance wheel and tires Assemblies.
4. Loose steering linkage: Repair or replace steering linkage parts as required.
5. Bent or damaged wheels: Replace wheels.
6. Severely worn or damaged tires: Replace tires.


...any of those sound like possibilities?:dunno:
 
collegeoffroad said:
for a mechanical noobie...how?

Pop the hood, have someone sit in the drivers seat with the car running.

Set the E-brake and chock the tires.

Have the assistant put the jeep in drive and sloyly press teh gas - the motor should react a little, but not all that bad - if it starts jumping - then you know that the mount is bad
do the same for reverse...
Tranny is a little more dificult - try looking at the mount from the rear - look for cracks or tears in the rubber (dont want the engine running for this part by the way...

I broke a driver side mount on the XJ, then replaced all 3 mounts at the same time - so i wouldnt have to again...
most people will tell you to go poly bushing aftermarket mounts - but my factory mounts are fine - and probably will be for another 160,000 (the mileage at the change)...



collegeoffroad said:
1. Warped or damaged brake rotors and/or drums: Machine or replace brake rotors and/or brake drums.
2. Loose wheel lug nuts: Tighten wheel lug nuts to specification.
3. Out-of-balance wheel and tire assemblies: Balance wheel and tires Assemblies.
4. Loose steering linkage: Repair or replace steering linkage parts as required.
5. Bent or damaged wheels: Replace wheels.
6. Severely worn or damaged tires: Replace tires.


...any of those sound like possibilities?:dunno:

Every single one of them.

another thing to look into is driveshaft balance

warped rotors will cause heavy vibration under brakeing
mud and snow and ice in the wheel can cause it to be unbalanced - clean the wheel...

check all thoes things - and report back...
 
loose bolts on your flex plate

your engine has a resonant frequency in the 2200 - 2400 RPM range. When you hit that range in each gear while accelerating, you feel the vibrations from the loose flex plate. Pull the inspection cover off and take a look.
 
Hey max i am having a vibration/ noise when i hit that exact RPM range you last mention (2200). I have checked my flex plate bolts and they seem ok, whats next ? Please take a look at my thread titled Rough engine Vib.

pete
 
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