Random violent shaking

[BDCarrillo]

Had this happen twice so far on the 92 SCLB 2wd truck... Yesterday going 45 hit a few small bumps in the road and the entire truck started shaking violently. Steering wheel was going left/right a couple inches and I was getting bounced vertically in the truck.

Pulled over and inspected tires, steering linkages, and suspension with zero obvious signs of failure. Cautiously got truck up to 60 without any issue.

Kind of reminded me of the death shake/wobble on later powerstrokes, but their steering is set up differently. My leading thought is old shocks letting the springs go ape.

Any thoughts?

 

[direwulf23]

I had this happen on my 2wd 94 a couple times and never quite figured it out. However, I did replace my worn out tires and balanced so I figure that could've been it. Hasn't happened in a while.

 

[mu2bdriver]

Carrier bearing/driveshaft center support bearing? This happened to me earlier this month before it completely let loose.

 

[LCAM-01XA]

Pulled over and inspected tires, steering linkages, and suspension with zero obvious signs of failure. Cautiously got truck up to 60 without any issue.

Throw the truck up in the air by the I beams, check wheel bearings and ball joints. Those are impossible to diagnose on the side of the road with the weight of the truck on them, they need to be "unloaded". Recheck your TREs then also.

In my experience dead shocks (or no shocks at all) usually cause the truck to start bouncing up and down like it's an Olympic swimmer doing the butterfly stroke. No side-to-side pulling and wheel shaking tho, not unless the road surface is a total mess.

 

[BDCarrillo]

Carrier bearing/driveshaft center support bearing? This happened to me earlier this month before it completely let loose.

I hadn't thought of that... Rubber is good on it and the bearing spun freely when I had the shaft out for transmission work. Any other indicators for wear on that center bearing?

LCAM: good copy on the diagnostics. I'll give those areas a check with the front up in the air. Shock replacement is on my to-do list as a preventative measure, stockers have 155k on them. Can you define TRE? Haven't seen that acronym yet

 

[LCAM-01XA]

Sorry, TRE = Tie Rod End. Mostly seen the offroad crowd using it...

 

[BDCarrillo]

Gotcha! I live by acronyms at work, after a thousand or so I tend to lose track of some.

FYSA I have a CDC EOC by COB tomorrow = Heads up I'm taking a test tomorrow.

 

[LCAM-01XA]

Sounds like a real SOB, GL!

 

[IDIoit]

inspect the steering box closely.

death wobble sucks!

worked on a dodge with the same issue, and found the pinion shaft in the steering box was toast.

 

[BDCarrillo]

Tie rod ends are good and snug, no play/wobble. Had like 5 violent episodes today, all at 45. I could feel a shimmy in the steering wheel and then it all went to hell. Didn't ease up with steering/brake inputs.

The last episode sent up a smoke signal from the right front. Starter solenoid nuked itself. Jumped terminals with a spare key and got it running. Got home and popped the front right wheel bearings out...

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Bunches of pitting and bad rollers. Both races are shot, looks like someone torqued the life out of the spindle nut then backed it off, because it about fell off when I looked at it. Rust all inside the grease cap.

 

[OLDBULL8]

If the inner cords in a tire let go, a wobble can resort. Only way to tell that I know of, is a tire balance check.

 

[BDCarrillo]

If the inner cords in a tire let go, a wobble can resort. Only way to tell that I know of, is a tire balance check.

New tires are definitely on the list, but I'd expect a constant shimmy from them. Got new shocks ready to go on. Wanted to work from the center of the truck outward on this issue, and the brakes are damn near new so I bet Bubba PO got me again.

 

[dunk]

Loose wheel bearings can do it. Get that fixed and check tie rod ends, steering box and mount (frame sometimes crack), spring bushings, shocks, ball joints/king pins. Basically anything that has any slop in the front axle can set it off. The heavier your tires the easier it is to set it off. Tiny free play in a few componenets can stack up. Make it all right and tight and you won't have a problem. Also get it aligned, caster is a major factor in death wobble.

 

[Greg5OH]

^ caster for sure. think shopping cart when the wheel starts going crazy..
coupled with loose box, bearings etc...whole mess

 

[franklin2]

....... steering box and mount (frame sometimes crack), .

The frame cracking happens more than you would think. Ford had a TSB out on these trucks for the rivet on the front crossmember wallowing out. It can crack around this rivet, and can also crack around where the steering box mounts. If you still can't find a obivious cause, I would start looking there. Get someone to turn the steering wheel back and forth (with the truck running) and see if you have any movement in the steering box.