Yet another 80 Series Vibration Thread. Replaced almost everything but the truck. (4 Viewers)

[12bit]

Past the point of losing my mind over this. I've got a 1994 triple locked 80 with around 220,000 miles. I've been chasing a vibration that you can feel in the whole truck for a very long time. The type where when you hit a small crack in the pavement, it's like it echoes throughout the whole truck (not a sound, but the feeling). Like a shudder or clattering feeling. Like something is loose. Basically, the truck drives like crap. You can feel it at any speed.

Here is what I have done so far:

• Front axle rebuilt (twice). New TREs (555), spindles (OEM), birfs (HDK), inner axles (OEM), bearings (Koyo), seals, etc. Bearings preload set. Steering knuckle studs torqued.
• Rear axle rebuilt.
• New OEM shocks. Dobinson stock height coils. All new OEM suspension bushings (radius arms, control arms, panhard). Triple checked torque.
• New OEM sway bar bushings, OEM end links.
• Pulled front & rear drive shafts. Replaced with new OEM.
• Tried 3 different sets of wheels/tires.
• Alignment done.

I've gone back and retorqued things multiple times. I am basically out of ideas and starting to wonder if it's not suspension related at all, but something like a misfire or motor mount. One other thing worth mentioning is that there is a whine coming from the center or front of the vehicle only under load. Seems to be diff whine.

Thinking about rolling it off a cliff. Any ideas?

 

[jeffro109]

The "diff whine" in your last statement could be the transfer case gears.

Engine and transmission mount bushings would be a good starting point to look at.

Body condition? Could something structural be loose/rusted apart?

 

[12bit]

The "diff whine" in your last statement could be the transfer case gears.

Engine and transmission mount bushings would be a good starting point to look at.

Body condition? Could something structural be loose/rusted apart?

Body and frame are solid. Very minimal rust. I should also add, there are no mods like bumpers, etc.

 

[NeverFinis]

Check for frame cracks around the panhard bar mount and steering box mount.

Check for cracks on all the welds on all mounts on both axles.

 

[Azca]

I might add to check all the panhard and rear control arm bushings. Ditto on sway bar bushings. Neverfinis is absolutely right on the cracks to check for as is jeffro 109 on the engine and transmission mounts. They can be cracked and can't see them. If nothing else, they will be hard as a rock by now...

 

[12bit]

Check for frame cracks around the panhard bar mount and steering box mount.

Check for cracks on all the welds on all mounts on both axles.

Thanks. I have checked these areas, but I'll do some more inspection.

 

[12bit]

I might add to check all the panhard and rear control arm bushings. Ditto on sway bar bushings. Neverfinis is absolutely right on the cracks to check for as is jeffro 109 on the engine and transmission mounts. They can be cracked and can't see them. If nothing else, they will be hard as a rock by now...

All suspension bushings have been replaced with new OEM. The motor and transmission mounts are original, though.

 

[truthdetector]

Body mounts?

 

[Azca]

Regarding the whine, two immediate things come to mind, have you cut off the resonator or does it have a hole in it? Have you installed under drive gears in the transfer case?

 

[Devils Paw 80]

Do you recall if there were any changes made to the vehicle directly preceding this problem developing or has it always been this way?

 

[TRAIL TAILOR]

Stock height or do you have a lift? If lifted, how tall?

 

[Old Nick]

^^^

New Tom Woods drive shafts sorted out the vibrations in my wife's 80. It's lifted a little over 3".

 

[NeverFinis]

First post he did write:

Dobinson stock height coils

 

[12bit]

Regarding the whine, two immediate things come to mind, have you cut off the resonator or does it have a hole in it? Have you installed under drive gears in the transfer case?

New exhaust all the way to the tailpipe, so I don't think it's an exhaust whistle/whine.

Transfer case is all stock.

 

[12bit]

Body mounts?

They seem to be OK, but I'm not ruling anything out.

 

[12bit]

Do you recall if there were any changes made to the vehicle directly preceding this problem developing or has it always been this way?

It's had some vibration since i got it. But it's either gotten worse over time, or my tolerance for it reduces after each additional parts purchase.

 

[Azca]

Okay, stupid question. Is the vibration more pronounced through the steering wheel indicating it is from the front suspension/steering? If so, as it was not mentioned, new steering stabilizer?

You also mentioned you rebuilt the front axle with new bearings. What about the rear axle?

 

[12bit]

Okay, stupid question. Is the vibration more pronounced through the steering wheel indicating it is from the front suspension/steering? If so, as it was not mentioned, new steering stabilizer?

You also mentioned you rebuilt the front axle with new bearings. What about the rear axle?

I did replace the steering stabilizer, too. It doesn't really feel more pronounced through the steering wheel.

Good callout on the rear axle. I rebuilt it last month and reused the rear bearings as they didn't look bad. However, it's been in the back of my mind and I do have a set of new bearings.

 

[tmxmotorsports]

I did replace the steering stabilizer, too. It doesn't really feel more pronounced through the steering wheel.

Good callout on the rear axle. I rebuilt it last month and reused the rear bearings as they didn't look bad. However, it's been in the back of my mind and I do have a set of new bearings.

Witch bearings did reuse and witch ones did you replace?

 

[12bit]

Witch bearings did reuse and witch ones did you replace?

All of the bearings in the front hubs and knuckles are new. Reused all of the rear bearings.