~70-75mph vibration

[mistaake]

I have a very noticeable, very annoying vibration in the whole truck and steering wheel between approximately 70-75mph. at 65mph or below it's not noticeable and it gets better the faster I go - at 90mph it pretty much goes away completely. but it sucks because I spend a lot of time at about 70-75mph lol.

Other than that the suspension and stuff seems tight. There is some play in the steering but it's the best of all the GMT400s I've owned in that regard.

Any ideas what could be the problem? I want to take it to the shop for them to diagnose but I want to have some educated ideas of possible issues before they throw parts at it.

Thank you very much in advance

1999 suburban k1500 124k miles

 

[jkeaton]

Out of balance wheel/tire or alignment.

 

[DaltonB98]

Yeah I agree with jkeaton, i've had the same problem with my car before. I think it's like 30$ or so to get them re-balanced then another 100$ for an alignment. If that doesn't work then there is might be a bulge in your tire? just something else to look for.

 

[GordonCustoms]

I had same issue with my truck when I first got back in 09 it only vibrated between 70 to like 75 as well and lower or higher it went away. Well I had small dent in my rear driveshaft. I picked up a used one and it was like new truck

 

[Bob L]

Tire balance vibration generally starts around 30 or 35 and then fades with higher speeds I would look at driveshaft U-joint issues also for higher speed vibration

 

[77Impala]

A friend of mine has a 96 ECSB K1500. Long story short his exact same issue turned out to be about a pint low on trans fluid. We chased all issues we could and determined it to be in the trans. A good trans shop found it.