Vibration at 55mph

My truck has had a wobble/vibration around 55mph and I losing my mind trying to figure it out. The vibration is most noticeable while watching the from passenger seat and I*can feel it in the steering wheel a bit as well. So far, Ive tried balancing the tires, different rims, and new tires as of today and the problem still exists. I have all new ball joints, axle u-joints, track bar, sway bar bushings, and alignment. The rear driveshaft has new u-joints and I'm pretty sure had it balanced a while back as well. The front driveshaft is out to eliminate that a a possibility.**The truck also vibrates at 75 mph, especially when accelerating on upgrades. I'm not sure if they are related or two seperate issues but its getting to where I no longer enjoy driving this thing. Any suggestions on what to check next would be appreciated. Thanks in advance!

What brand/model/size of tires and rims ? Are you installing top quality brand name steering and suspension parts or just cheap no-name Chinese junk that the chain store auto parts stores sell ? Are all the suspension bushings and steering parts fresh ?

Vibes that appear at about 50-55 mph and disappear at about 65-70 are almost always a tire/rim issue. Are you getting your tires balanced at a brand name retail tire store by some kid just out of the vo-tech, or are you going to a locally owned independent tire shop with a Hunter Road Force balancer ? Most retail tire stores only have a balancer that tells the newest employee in the shop where to put the weights. A road force balancer checks both the tire and the rim for out of balance conditions and cross balance conditions and the tire technician gets a readout that informs him if the tire needs to be rotated on the rim to equalize any imbalances between the two.

A vibrations that is usually only at accelerating or only at deceleration would typically be a u-joint or driveshaft balance issue.

Stock or lifted ? My 97 does it just a little (lifted) When stock i had no vibs

Spicer ball joints and u-joints, moog track bar. I always use good part, learned my lesson long ago. Tires are Falken at3 and were just installed today. Ive had a road force balance done before but that didn't help. You can see why I'm a my whits end.

no lift, new stock rear springs

Stock rims ? Loosened and re-torqued the lug nuts ?

I have a set of General Grabber AT3 on stock aluminum rims and two of them will not balance correctly, even with a Road Force machine. I have had to resort to ceramic balance beads to get them to run semi-smoothly. BFG A/T and M/T, Firestone Destination A/T's and Kumho AT51 have all been smooth tires that required minimal balance weights.

Ive swapped tires, rims, had a road force balance done and finally got new tires today. Nothing has helped.

If not tires/wheels, and the suspension or steering is not suspect, that leaves drive line issues as the next area to suspect. Install the front driveshaft, remove the rear driveshaft and go for attest drive on the same route that causes the vibes.

Tim_MN said:

If not tires/wheels, and the suspension or steering is not suspect, that leaves drive line issues as the next area to suspect. Install the front driveshaft, remove the rear driveshaft and go for attest drive on the same route that causes the vibes.

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Won't that puke oil out of the rear xfer case output? How are the wheel hubs/bearings?

Is it ok to drive 55 + mph with only the from driveshaft installed?

brielly said:

Is it ok to drive 55 + mph with only the from driveshaft installed?

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Yes

lawsoncl said:

Won't that puke oil out of the rear xfer case output? How are the wheel hubs/bearings?

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He never stated what year, but it won't if it's a 97+.

RCP Phx said:

He never stated what year, but it won't if it's a 97+.

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'96 also got the newer style output.

As for other things to inspect in pursuit ofthe vibration, have front axle U-joints been checked?

It might also be worth trying to eliminate brake rotors/drums as a cause. I know that sounds like an odd one, but I had a friend who fought his way through a similar issue as yours and it wound up being rear brake drums. He isolated that problem by clamping off the flex line and running the truck without rear brake drums. The difference was night and day. A new set of drums solved the problem. Getting to that point was a long road however.