97 GMC Suburban K1500 4x4 5.7l high speed vibration/shaking/wobbling

My 97 GMC Suburban has some shaking or vibration going on at higher speeds. It starts around 65 mph, is worst around 70 mph, and goes away above 75 mph. It is not a clanking or knocking, it is more like a wobbling or bouncing. I believe it is strongest when I accelerate and sometimes it is as bad as making the whole car shake. Any ideas? Thanks everyone!

Pardon my ignorance. Do you think these two issues (the wobbling and the steering play) are caused by the same problem?

Is your Suburban configured as always in 4WD, or does this happen when it is in the 2WD mode? If the latter, could be a problem in the rear drive-shaft of some sort. Do you hear any squeak-like sounds at lower speeds, around 30 mph, especially when driving next to a good sound reflector, like a bus or van?

Yes, worn out ball joints.

It is not always in 4WD, I can shift between drive modes. So far I have only noticed the issue in 2WD, I never drive that fast in 4WD. No squeaking, also no knocking or clanking, feels more like a tire bouncing or out of balance.

I swear, I have had two different shops look at my front end, both did work on it and charged me a bunch of money, but none fixed the issue.

What I am saying is that the issue is getting really frustrating. Especially since the wobbling and steering issues are keeping me from traveling longer distances, camping, etc.

Well, that’s a definitely possibility then … lol … tire balance is easy enough for a shop to check. Out of balance tire wouldn’t usually show up more on accel though. Unless you were accelerating through the wheel’s natural out-of-balance resonance speed. To test, go above that speed and coast back down through it with foot off gas. If it shows up then too, tire balance is likely culprit.

A problematic rear drive shaft can often be spotted by a shop tech simply twisting on it while it is on a lift. There should be no play at all. If there is play, suspect worn u-joint or less likely, spline problems.

For tire bounce, as someone to follow you. If tire is bouncing up and down they’ll notice it. Tire bounce could be a suspension system problem or a faulty tire. Any unusual tread patterns on any of the tires?

As mentioned above, the steering problem could be causing this too. Since you know that’s a problem, unless you spot something otherwise that’s obvious, suggest to focus on that one first.

Tires out of balance is definitely a possibility. Worn ball joints typically show up as a squeak or clunk over bumps rather than a vibration, in my experience. Not to say that they can’t cause a vibration, I just haven’t experienced that. I’d be looking at tires, front and rear driveshafts (u joints), and cv joints if I was looking for a vibration on that truck. But, it’s a 20 something year old 4wd, so there’s lots of possibilities. Great truck, btw. Let me know if you have questions or if we can be of more help. It might take some investigation, lots of moving parts on a 4wd.