I was driving home on the freeway going about 60 when I hit this pot whole that spanned the entire lane. Upon hitting it the truck did the usual lurch, nothing unusual, but then it started rocking back and forth uncontrollably, as if I were going over super bumpy asphalt, but seeing as I was on a newly paved road, it wasn't the road, it was the truck. I instinctively checked all my gauges but they were all normal, so not knowing what to do I pressed on the brake. As my speed decreased the rocking slowed and at around 40mph it stopped and the truck ran fine the rest of the way home. So what in the hell caused that? It lasted maybe 20sec but made me feel as if my truck was gonna fall apart under me. Could it be the alignment or something? Any help would be appreciated.

My truck's a '99 Club Cab 5.2L V8 with no mods.

 

Assuming you have a 4x4! Check the Trac-bar . Also do a search on here for Death Wobble.

 

+ 1 on trac bar

 

My trucks not a 4X4 though. . . thanks for the fast replies!

 

Well first of all, that's a bit of info you should provide in your sig, don't you think?

And second, describe "rocking back and forth". Obviously I mis read that and assumed you meant the steering wheel was shaking.

 

I do need to work on a sig =P
The entire truck was shaking violently. To the point where when I looked into the rearview mirror it was so distorted with movement that I couldn't make out whether there was a car behind me or not. It was as if the truck was going to vibrate itself apart. The steering wheel was indeed shaking, as was everything else, however. It was as if the lurch that I got from going through the pot hole continued to happen over and over again as I continued driving. You know that feeling, when the truck bounces about rapidly after going through a pot hole at a fast speed? It was like that but for a 20sec duration on a newly paved road.

 

It is indeed a death wobble, but some 2 wheel guys will have to chime in here. IMO, the first thing you need to do is get another person and have them turn the steering wheel left to right, while you look underneath (without the truck running) and see if any steering parts are loose. Then raise the front off the ground and grab the tire at 6 and 12 o'clock and see if anything is loose,(wheel bearings, ball joints). Also grab at 3 and 9 o'clock and push front to back to see if the control arm bushing's are shot.

 

A Hawaii truck wont have corrosion issues like the snow guys here, but it's possible due to the sea air. Check your body mounts.

Does the shaking come from the front or the rear of the truck? Just knowing that will help a lot.

 

Thanks for the tips Zman17, I'll try that out later today. I do live right up the street from the beach, so that would cause some corrosion. I'll check my body mounts while I'm at it, Viper37, thanks for the tip.
It seemed like the shaking could have been originating from the front of the truck, as the cab was shaking madly and the brunt of the impact with the pothole was taken by the front. Thanks again for all the replies!

 

Jack up the front end, give each of the tires a nice love kick, make sure your ball joints aren't shot. Examine your bushings and make sure they are all there. (some cracking is ok, but if there are chucks missing that is a problem) Basically go through your front suspension and make sure nothing isn't moving how it shouldn't.

Also, while you are at it... Check your motor mounts.