2022 Silverado LTD - Vibration at 70+ mph (Diagnosis Help)

fondupot · August 24, 2023

Hi all, my truck has developed a really annoying drive train vibration that I can feel in the floor board and in my seat, I do not feel very much vibration in the steering wheel. The truck is a 2022 Silverado LTD Custom, 4x4, Crew cab, short bed, 2.7T 8 speed. Currently just under 76,000 miles on it. So out of warranty.

It has a relatively new set of Michelin LTX Defenders on it (around 15k miles on them). When installed they were perfectly smooth. Over the last 16k miles the truck has developed this annoying vibration at speeds 70+. I do a lot of interstate driving so 70+ is where I typically drive, and it's really bad. I also notice that the vibration seems to get worse when going up inclines at these highway speeds. At first the vibration was subtle, but over these last several thousand miles, its gotten progressively worse. The truck is really smooth at all speeds up to about 70 mph. I've been doing a lot of my highway driving at 67 mph because if this lately, and other than feeling like a turtle on a drag strip, the truck rides and feels very smooth at this speed. Once you hit 70, it starts to vibrate. 72-73 is probably the worst. 77-80, it's less intense, but still present. 80+ it gets a little worst again. I rarely hit 85, maybe only while passing.

I've had Discount Tire (tires purchased from here) rotate (front to back and side to side) and road force balanced the tires twice. No change. Discount Tire swears up and down the tires are fine. I trust them with about 80% certainty.

I'm starting to think maybe its drive train related, but still the 20% uncertainty that it could be the tires remains. If it is drive train, there's a lot that it could be...

-transmission (I don't think so because the vibration remains when I am costing in N at highway speed)

-transfer case (I don't think so because the vibration persists in 2wd, Auto and even 4hi at highway speed, I know its not good to run 4hi at 70+ but I only did it to test for a short period)

-u-joints - maybe, but the vibration would also be present at lower speeds too, right? Also no apparent noise or obvious grease on the undercarriage around the u-joints

-driveshaft - maybe, no apparent damage, but maybe it's out of balance?

-rear differential - and entire host of things could be going in the rear diff, bearings, races, axles etc.

The truck is going to an independent shop for a diagnosis tomorrow. But I wanted to get some thoughts on here.

Thanks in advance.

silveradosid · August 24, 2023

your systems still point to a tire, i had michelins on my truck that where great until higher speeds and went thru the same as you did, eventually the tire exposed it self with a buldge in the tread. at lower speeds and even on the balancer it did not show that the tire had a separation going on inside of it

jaxcam02 · August 24, 2023

I'm not going to lie, some trucks just have weird vibrations. I had a Colorado that had similar issues that I was unable to track down. Outside of just throwing parts at the issue and tightening all suspension bolts and nuts it is just a crap shoot at figuring out the issue. If I were you I would find another set of wheels and tires to completely eliminate that as a factor and go from there.

repairman54 · August 24, 2023

Could be the 8-speed trans. convertor lock up going in/out. Fluid change with M1 blue label HP fluid was an initial fix. Google up convertor shudder in 8 speeds.

Bikerjon · August 24, 2023

Very hard to diagnose. Floorboard vibration and not so much vibration in the steering wheel points to a rear wheel but you have had the tires rotated. You are asking for thoughts or opinions so here you go. Give the independent shop a shot, if they dont come up with a fix. I would closely inspect your wheels for damage or bending, raise the vehicle and slowly rotate all tires while visually inspecting for tread separation (you can usually spot tread separation by tread deformation or an out of round condition). If you dont find the problem after that I would replace the tires.

Good luck! I like your vids on youtube.

fondupot · August 24, 2023

4 hours ago, silveradosid said:

your systems still point to a tire, i had michelins on my truck that where great until higher speeds and went thru the same as you did, eventually the tire exposed it self with a buldge in the tread. at lower speeds and even on the balancer it did not show that the tire had a separation going on inside of it

Thanks for the input. I just dropped the truck off at my independent shop and they're gonna run it thru the ringer. Will see what they can turn up. Tires were good on initial install about not too long ago, about 16k miles. it's only been the last few weeks this vibration came up.

2 hours ago, jaxcam02 said:

I'm not going to lie, some trucks just have weird vibrations. I had a Colorado that had similar issues that I was unable to track down. Outside of just throwing parts at the issue and tightening all suspension bolts and nuts it is just a crap shoot at figuring out the issue. If I were you I would find another set of wheels and tires to completely eliminate that as a factor and go from there.

Truck was smooth up until recently. This just popped up the last few weeks, and has gotten progressively worse.

2 hours ago, repairman54 said:

Could be the 8-speed trans. convertor lock up going in/out. Fluid change with M1 blue label HP fluid was an initial fix. Google up convertor shudder in 8 speeds.

I'm aware of the 8 speed issues, I do not think it's from the transmission. Transmission was serviced at 50,000 miles (26,000 miles ago). Flush, Fluid and Filter. If it was the transmission, the vibrations would go away when coasting in neutral. They remain.

1 hour ago, Bikerjon said:

Very hard to diagnose. Floorboard vibration and not so much vibration in the steering wheel points to a rear wheel but you have had the tires rotated. You are asking for thoughts or opinions so here you go. Give the independent shop a shot, if they dont come up with a fix. I would closely inspect your wheels for damage or bending, raise the vehicle and slowly rotate all tires while visually inspecting for tread separation (you can usually spot tread separation by tread deformation or an out of round condition). If you dont find the problem after that I would replace the tires.

Good luck! I like your vids on youtube.

Yea, for sure. It definitely seems like something out back. The truck is at the shop now and they are going to have it for the rest of the day. Hopefully hear something back.

Thanks all for the input.

fondupot · August 26, 2023

Just to close the loop on this. It ended up being the balance on the tires, luckily it was an easy fix.

The independent shop I used said all the tires had 4-8 oz more than they needed. They recommended breaking the tires down, balancing the wheel, re-mounting the tires then re-balancing the assembled wheel/tire. I said go for it. Cost was $95.

Got the truck back the same day (Thursday), and drove it at highway speeds 300 miles on Friday. WAY. SMOOTHER. All the way up to 85 mph. I mean, not Cadillac smooth, but considerably better than it was before, and after all I am a realist and a pickup truck with leaf spring suspension can only get so smooth. I'd say 98% of the vibration was eliminated. I'm satisfied.

This really has tested my faith in Discount Tire, because I have been using their shops for 20 years, but if they cant seem to get a balance correct, what good are they? I'll be using my new independent shop from now on for my tire balancing needs.

Thanks all.