O.K. guys...searched like crazy, not sure I found an answer. (1 Viewer)

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Vibration: Does not exist while accelerating, only slight while maintaining speed, but noticeable when decelerating. Wife says she has noticed it getting worse.

'97 Cruiser 122,000 miles
Slight wearing of outside edge of RF tire
Recent birf. repack
New rotors (front)
New wheel bearings and races
New trunnion bearings and races
Repacked rear bearings
tires rotated and balanced
Both drive shafts removed inspected, greased (all O.K.)
TRE's seem to be fine (no excessive movement).
Shocks are a little soft but not "blown"


*****Have not checked "toe in" yet!*****

Odd that it would be worse when decelerating...any ideas? I've read quite a bit of what has been posted in the past, but it doesn't seem anyone came up with a solution.
 
Tools R Us said:
What lift is on it?


Not lifted. Everything stock....I would expect a caster problem or some vibration with a lift but mine is stock (so far).
 
I also have this same problem.. but only after my lift.
I feel the vibrations comming from the floor where my foot is.
I was told that it could be
A. front drive shaft off 180 deg.
B. front end too high
C. front drive shaft out of ballance

May be something else too... but its something to chew on

-Ron
 
Project FJ80 said:
I also have this same problem.. but only after my lift.
I feel the vibrations comming from the floor where my foot is.
I was told that it could be
A. front drive shaft off 180 deg.
B. front end too high
C. front drive shaft out of ballance

May be something else too... but its something to chew on

-Ron

Hey Ron...

If your drive shaft was off 180 degrees then it would be back in the same place it was before you turned it.

I think you mean 90 degrees which is the correct phasing (in our case, 'out of phase') for the front drive shaft.

If you did the caster correction bushings in your front control arms and you are still getting issues, then more than likely you have driveshaft (front or rear) issues. You can easily isolate this by removing one drive shaft, locking the CDL, and driving to see if you get the vibrations. Do it again with the other one out. You should be able to trouble shoot your issues pretty quick. Also, don't forget about your u-joints which tend to cause problems like this as well.

-o-
 
I would expect a caster problem or some vibration with a lift but mine is stock (so far).

Driveshaft angle vibration was what I was ruling out. See if you can make it do it parked, by shifting reverse and with your foot firmly on the brake slowly increase the RPMs, if not try drive. Then with a helper you can find it, look for something in the drivetrain rubbing on the frame or body transferring the motor vibration to the body, many times it's exhaust related, broken mount, etc.
 
I was thinking with 360 deg. in mind. but yes .. 90deg.
I got the slee 6" lift kit .. came with everything... chris says too lite up front .. (no arb bumper or winch yet) also have a brand new front drive shaft which was sent.
I also get the vibration at a high steady speed 55+ and then it gets loud as soon as you let off the gas. sounds like them trucks that pass you with 49" tires.. or like something is about to break.
-Ron
 
LandCruiserPhil said:
Flint do you feel the vibration in the steering wheel or in the seat of your pants?


Very slight through the steering wheel. Almost like front end shimmy but less pronounced, and definitely more noticable when you let off the gas at highway speeds. No occurence of it at all when accelerating hard, but a slight amount under moderate throttle.

Almost sounds like V/C (T-Case) problem.

Engine feels just a little sluggish to me also, even though I just replaced plugs, wires, cap, rotor, set timing. It has been running fine. No CEL or anything...who knows?
 
flintknapper said:
Very slight through the steering wheel. Almost like front end shimmy but less pronounced, and definitely more noticable when you let off the gas at highway speeds. No occurence of it at all when accelerating hard, but a slight amount under moderate throttle.

Almost sounds like V/C (T-Case) problem.

Engine feels just a little sluggish to me also, even though I just replaced plugs, wires, cap, rotor, set timing. It has been running fine. No CEL or anything...who knows?

So it is not speed related?
What do you get when you are at speed and put it netural, releasing the load off the drive train?
 
LandCruiserPhil said:
So it is not speed related?
What do you get when you are at speed and put it neutral, releasing the load off the drive train?



Don't know yet, I'll have to try it tomorrow. That would eliminate "input" loads from the drivetrain. My guess is that I'll still get the vibration...because as I said; it seems to be more noticeable when not under power (coasting or decelerating). I'd be taking the torque converter out of the equation but the rest of the driveline from the wheels back to the T-case would still be driven by vehicle momentum.

I guess my question is: What are we testing for?

I'm open to ideas.
 
Checked the "toe-in" this morning and it was dead on 1/8". All TRE's in good shape.
Wifey needed the beast to go run errands so I'll have to try some driveline tests later.
Any other ideas in the mean time would be appreciated.
 
do you have a CDL? Lock it and try the same test. Did it go away?

Remove the front driveshaft and test...what happened?
Replace front and remove rear...test...what happened?
 
Safado said:
do you have a CDL? Lock it and try the same test. Did it go away?

Remove the front drive shaft and test...what happened?
Replace front and remove rear...test...what happened?


Yes, I have the CDL. I just had the drive shafts out of the vehicle yesterday to check for wear in the splines and U-joints. My first thought was drive shaft inbalance but they look good (no dings, not missing weights, not bent, everything tight). Checked the flanges at both diffs. and both outputs of T-Case, everything was Okie Dokie. This is strange.

I'll give that a try....at least it might isolate the problem to the front or rear of the vehicle.
 
The vibration is greater on decelerating is the strange part. Given that your vehicle is stock makes drive line and tire issues much more forgiving then a lifted truck with large tires.
A couple more things I would look at -
Is the vibration felt thru the transfer case shifter lever?
Check your front pinion. Is there any movement in and out by pulling and pushing or when you twist it back and forth by hand?
Is the front pinion seal leaking any?
Does the vibration increase the more the vehicle decelerates and just stop when you reach a given lower speed?
The fact that you feel it in the steering wheel tends to point to the front of the vehicle.
 
This may be totally off, but I had a very similar problem that was caused by bad gas from winemmucca, NV. It would be fine under load but at cruising speed or going downhill the engine would run really rough but there was only a slight deviation on the tach. Filled up in Jordan valley and all was well. I am also missing the little plug wire clips for my cap and one of the wires fell off while traveling, causing a vibration that seemed drivetrain related until I stopped and then it was obvious. Just something to check.
Good luck,
Dan
 
LandCruiserPhil said:
The vibration is greater on decelerating is the strange part. Given that your vehicle is stock makes drive line and tire issues much more forgiving then a lifted truck with large tires.
A couple more things I would look at -
Is the vibration felt thru the transfer case shifter lever?
Check your front pinion. Is there any movement in and out by pulling and pushing or when you twist it back and forth by hand?
Is the front pinion seal leaking any?
Does the vibration increase the more the vehicle decelerates and just stop when you reach a given lower speed?
The fact that you feel it in the steering wheel tends to point to the front of the vehicle.

No more vibration through the t-case than normal (a certain amount is to be expected...heck, its got a dampener on it), neither pinion seal is leaking and there is no slack in either the flanges or the pinion pre-load. Rotation of the pinion gear before it meshes with the ring gear is minimal and so it seems the backlash is correct.

Vibration does not increase as vehicle slows but does go away at a certain speed (not long after letting off the throttle). Light acceleration, and deceleration seem to cause it to occur. Motor runs perfectly smooth at idle, no CEL, but seems slightly off on power.

Exhaust flow problem?
 
LandCruiserPhil said:
I cant see how you would feel it in the steering if it was the exhaust.

Is the vibration RPM related or MPH related?



Agreed, I don't see a connection either. There is a slight feel through the steering wheel but mostly "seat of the pants". Not real bad but noticeable.

Not MPH....and really not RPM (I know that sounds funny), its more like power applied (or not) related. Scary...because it could point to the V/C in the t-case.

I'm going to go drive it right now...and do a little more assessing.
 

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