front rumble puzzler, not ujoints or spindles, help! (1 Viewer)

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Hoosier Daddy

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Jul 1, 2005
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I have a 95 with an Ironman 2.5 lift, Arb bumper, no winch, and a Mr Gasket 1" (3/4" in reality) spacer in the front to compensate for the ARB. I have the Slee caster bushings.


  • Truck has developed a rumble/mild vibration at speeds above 60 mph when in-between slowing or accelerating (ie, no load on drivetrain).
  • I think I have recently started to notice it a little bit under similar conditions around 40 mph, although not nearly as pronounced as at higher speeds.
  • It seems to be worsening with time.
  • Onset was well over a year after the lift and caster bushings, but before the ARB and Mr. Gasket spacer.
  • Adding the ARB bumper and later adding the spacer did not affect the rumble noise or vibration. (The ARB had dropped the front about 3/4 inch, so I added the spacer.)
  • Removing the rear driveshaft does not affect it at all.
  • Removing the front driveshaft makes it go away completely.
  • I had both front U-joints replaced with Toyota OEM without any change. I later tried switching the driveshaft orientation to in phase, with no change.
  • The front axle was re-done a while back, with all new bearings. Wheel bearings are tight. I was sure I had greased the spindle bushings well, but in desperation I tore it all apart and double-checked. All good, but greased them up some more for good measure. No change. Spindle bushings seemed to look normal.

I searched Mud and came up with the front pinion bearing or transfer case output bearings as possible culprits. I removed the front driveshaft and checked the flanges for any up/down, side to side play, and found none. Just the expected mild rotational slack in the differential flange and a tiny bit of in/out on the transfer case flange. No leaks from either the pinion or transfer case.

I'm stuck. What am I missing?
 
Slip joint in the front drive shaft. Is there any slop in it at all? Sounds like you have done all the right stuff. If the front end rolls down the road without the driveshaft on, that clears a bunch of stuff that could be the problem.

I can say that my rear driveshaft had a rumble at 60 MPH for a long time, and was fixed after getting an entire new driveshaft. I had changed the u-joints myself twice (one of those times paying for a new balance) before replacing the entire shaft.

Only other thing to check would be the diff fluid in front for crap....:meh:
 
Boy sounds just like mine did. It was the splines in the slip joint drive shaft. But guess you have ruled that out. :(
 
Boy sounds just like mine did. It was the splines in the slip joint drive shaft. But guess you have ruled that out. :(

:hmm: Your post gave me an idea. I'll try to borrow someone else's driveshaft locally and see if I can totally rule it out.
 
It was a pretty irritating vibe I got under the same conditions you described and slowly got worse of the last months. I knew I was doing a complete front end axle swap and figured we would find the source during it. I thought ujoints, bearings, linkage, etc, until a buddy said dude your front drive shaft isnt sounding so good. I had not even thought about those spline

Anyway hope yours is as simple as that.
 
I had the same rumble, the slip joint seemed fine to until i separated and found rock hard grease at the bottom of the spline. I dug it out, cleaned it, regreased and rumble gone.
 
Is there any science to isolating where the vibe is coming from (diff, shaft, transfer case) based on how much the vibe can be felt in the TC shift lever?
 
Well you isolated it by stating in your first post that removing the front driveshaft made the noise go away. Also one of the driveshaft weights could be not in the correct orientation or missing. I'd have the DS rebalanced.
 
Well you isolated it by stating in your first post that removing the front driveshaft made the noise go away. Also one of the driveshaft weights could be not in the correct orientation or missing. I'd have the DS rebalanced.

Oops, my wording was sloppy. I meant isolating it between the driveshaft, TC output bearing, and diff carrier/pinion bearing. AFAIK, removing the shaft will affect a vibe in any of those locations.

No missing weights on the DS but I may very well get the balance checked if I can't find a known good shaft to borrow.
 
could get a set of the vibration recorders (mechanics ears or stethoscopes) and clip one lead to each item other than the driveshaft of course.

Sounds really familiar to what mine (and several others) do. I had replaced the front driveshaft with one having new U-joints and rebalance, no change. I put new wheel bearings in and I put in new bushings in the spindle though the old ones looked OK as a last step to fix the noise that was exactly like you describe and getting worse. Upon removal, the PS bushing had rotational marks on it. The spindle fits much more snug on the birf shaft after replacing the bushings.

I also took out the front diff and tightened up the side ?bearings? an equal amount of notches on each side to take out some slack.

Noise is gone now. Occasional noise from the front end when I hit a bump or just the right combo of turn/lean and throttle but the issue is fixed.
 
have you removed the front shaft and used an angle finder to compare the degree of tilt on the pinion shaft and t-case output shaft? they should be exactly the same after the lift and caster correction. If not, you will get a vibration and that rattling noise.

sometimes a cv shaft will fix the issue but then the pinion shaft has to be on the same slope as the drive shaft tube. It's hard to get it correct on an 80.
 
So did you get this figured out? Mine is doing the exact same thing after I installed my lift. I have some cc bushings and am hoping that's the problem so I can have it running right again
 
I haven't found anyone locally to loan me a driveshaft yet, so last night I went ahead and ordered a set of chassis ears. Probably won't have an answer this week, but will update the thread when I do.
 
It's the driveshaft. I have the same thing going on. I even went as far as replacing the front 3rd member thinking that the original needed an rebuild. That didn't change a thing. I replaced both front and rear driveshafts after having a new set re-jointed and balanced. Still no change in the noise. About once a month I have been climbing under the truck and re-greasing the u-joints, that is the only thing that will effect the noise. It doesn't go away completely but it gets much less annoying. I'm about to start looking for someone nearby with a DC front shaft and see if I can borrow it for a short freeway run to see if that is the cure. I have the Ironman 2.5" lift and metaltech 3.5* caster plates. After an alignment I have 3* caster.
 
:D Im telling you it's hardened grease in the slip joint.
 
I wish. Based on your post I took it all apart and cleaned every bit of grease out of the joint. Gave it some light grease, made sure the slip joint moved easily through its full range, and took it on the interstate. No luck. :frown:
 
I wish. Based on your post I took it all apart and cleaned every bit of grease out of the joint. Gave it some light grease, made sure the slip joint moved easily through its full range, and took it on the interstate. No luck. :frown:

Okay, well just giving it a shot. Only thing i can think of is out of balance DS.
 
This noise started immediately after I did my 2.5 lift without cc bushings. I am hoping that installing those today will remedy it for me
 

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