Help! (another driveline vibration thread)

[Jacques Villeneuve]

Here is the latest update:
The tech did not use the electronic microphones to listen for the source of the vibration (he looked at the truck and said "It's not a Ford or GM...I have never seen such a front end. I wouldn't know how to fix it." I didn't ask him to fix it, just pinpoint the source of the vibration with the microphones. I gave up with him
I did install new brass spindle bushings (thanks Dan ). One spindle had a small groove on the inner bearing side but very minor and only on one half of the spindle. The thrust washers (both sides) had a groove in them so I think that the outer bearing race may have been spinning on it. I used new thrust washers.
The vibration is still there.
To summarize:
- 97 LX450, 150k miles
- after hitting a speed bump at 10 mph in a parking lot the vibrations started right thereafter on the road
- vibrations at 30 to 55mph on the gas and on deceleration
- replaced u-jounts and had the drive shafts balanced
- the drive shafts are in the correct phase
- the splines of the drive shafts are not over lubed
- rotated the tires
- drove the truck with the CDL locked and took out the rear and then the front drive shaft. The vibrations go away when the front drive shaft is removed and only using the rear drive shaft. The vibrations are greatly diminished if the only front drive shaft is used. With both drive shafts in, the vibrations are greatest without the CDL locked and are somewhat diminished with the CDL locked.
- replaced the brass spindle bushings on both sides (the original ones did not look dry). PS. Harbor Freight has a neat tool to pull the bushing out...worked very well ( IH8MUD Forums - View Single Post - Brass Spindle Bushing Removal Tool ).
- got under the truck with all four wheels off the ground, all diffs locked and everything in neutral -> pushed and pulled on the drive shaft ends and no play was noticeable
- while I was at it over the last two days, I replaced the rear brake rotors and pads (very smooth braking instead of the pulsating I had before)


What now ?
Thanks in advance

PS. - when I beat on the brake drum to get it off, it started snowing harder and then stopped when I stopped->maybe I should get a job as a rainmain! Man, it was cold in the garage and winter isn't really here yet.

 

[96r50]

Could it be something in the centre diff? If it changes with the removal of a driveshaft and seems to change while locking the centre diff it would seem to be the common point in the system, would it not? (I have not read the entire thread)

Where in Southern Ontario are you? I'm currently in Peterborough. Slightly east, but if you're around I wouldn't mind trying to help.

 

[Jacques Villeneuve]

Could it be something in the centre diff? If it changes with the removal of a driveshaft and seems to change while locking the centre diff it would seem to be the common point in the system, would it not? (I have not read the entire thread)

Where in Southern Ontario are you? I'm currently in Peterborough. Slightly east, but if you're around I wouldn't mind trying to help.

Thanks for the offer. I'm about 10km West of London in Delaware.
A few more things I should mention:
- I checked all the brackets for the sway bars, steering components, etc. and none appear broken-> all welds are as they should be
- the nuts holding the trunion bearing are all tight
- the birfs do not click
- the grease in the birf area looked OK
- all diff fluids were replaced and all looked good
- there was little sign of metal on the magnetic drain bolts of the diffs

 

[Jacques Villeneuve]

I have read that adding weight to the front end might get rid of some of the noise from this post .. IH8MUD Forums - View Single Post - Front Drive Shaft grrrrrrrrr findings so far. . . I did notice that the vibration seemed less when the suspension was bottoming out as I drive over a long (say 10 feet) smooth bump on a road at about 50mph.
When I hit that bump that casued the original issue, could the suspension been twisted somehow so that the driveshaft angles changed relative to the pinions?

 

[Jacques Villeneuve]

The vibrations are still present so I pulled the front driveshaft again (the temperatures have gone up to 40F today). I noticed some play in both the front and rear U-joints. I have thicker c-clips (0.060' vs 0.050") to put in to see if the slack is taken up and to see if this affects the vibrations.

There is no play sideways on the front diff pinion companion flange.
One question. I pushed/pulled on the front output of the T-case. There is no slack sideways. There is some rotational slack but there is also a small amount ~ 1/32" of in and out play. Is this normal?

 

[Jacques Villeneuve]

Got it fixed.

Orignally the front drive shaft was in phase. I put it out of phase. That didn't work. I disassembled it again and rotated the the yoke 180 degrees. I also noticed some play in the new U joints so I put in thicker C-clips (I had to bang one of the cups in further). I slapped it back on and the vibration is gone! Thanks to all who helped.

 

[scottm]

Cool, glad it all worked out.

 

[reconranger]

Cool, glad it all worked out.

My memory is going. What happened to your driveline vibration? Thanks in advance.