Chevy shake, vibration at highway speeds, my fix and what I found out

danno0676 · July 14, 2022

My first post, I joined to try and help others.

Quick skip to the fix, the drivesahft.

I recently purchased a 2015 Silverado, 4wd, 4 door, 6.5 bed, 5.3, 6 speed auto.

First mod, replacement trans to fix the torque converter shutter.

Second mod, upgrade the factory 18's to reproduction 20's with 275/60/20 Nitto terra grappler G2's.

I drive from VA to PA for work, usually I camp out in the right lane and cruise around ~60, the truck felt good, not smooth, but nice enough after moving from a 2002 F250 CCLB 7.3 that was slightly lifted. On a trip to FL I picked up some speed, 70+, and thought I must have a tire out of balance. At 75+ it was downright awful.

I would associate the vibration at 70 to a bad u joint, a high speed vibration, but it wouldn't go away with throttle modulation. At 75+ it changed to a more violent shake/wobble. Once in FL I had the tires rebalanced, the 60 below speed was smoother but the 70+ unchanged.

Once I had more time I did some intense internet research and found lots of interesting paths for diagnosis.

First was easy, I was very concerned after reading multiple threads about the G2 tires having vibration issues. Having worked in the auto industry for years in the past, and hearing the "wives tales" about "low quality" aftermarket wheels I was unconcerned about the wheels but I checked them anyway, tires and wheels straight and true.

Next, while it was on the lift, I grabbed pry bar and with the truck running in gear I propped it beside the rear driveshaft and watched/listened to it scrape on and off of the pry bar. Shut the truck off and grabbed a run out gauge, 49 thousandths out.

Next was find a driveshaft. First I tried to source on locally, no one would make one but they were glad to order one for me. So I started to scour the internet, mail order custom made high power/high speed units, or mass production units. I found a company called Powertrain Industries that looked the best, great reviews and all Spicer components on a full 5" tube for about $700-$800. A little more research and I found PTI was recently purchased by Dorman. I called Dorman to get some specifics on their shafts, the person I spoke with confirmed that and told me that they moved all of the shaft production to PTI (the stock photo on the Dorman shaft is a direct image from PTI as well). So in the end I ordered the Dorman shaft for about half the price, installed it, and after a 90mph test drive the truck is as smooth as a Cadi.

Hope this helps someone.

sk · August 17, 2022

So which Dorman p/n did you order?

danno0676 · August 18, 2022

On 8/16/2022 at 8:03 PM, sk said:

So which Dorman p/n did you order?

946-633

That is the number for a crew cab, 6.5' bed, 5.3 4wd. There are a million different wheelbases offered for this truck, different shafts for the v6 model as well because it has a different rear diff (I think).

After some communications with eBay member
https://www.ebay.com/usr/ultimate_auto_parts?_trksid=p2047675.m3561.l2559

They ARE Dorman and sell quite a bit cheaper than anyone else.
You can use https://www.dormanproducts.com/ to do a Year Make Model search.

Frankthetank91 · July 30, 2023

Thank you, I just bought the same truck and am having the same issues. Going to trouble shoot this first.

J OBrien · June 23

You

I just bought a 2023 Silverado 1500 High Country 5.3 (L84) with 10 speed (MHS) 4x4. It shakes, shutters or vibrates from start through all gears at any speed! $75,000 truck! Help! John OBrien

MikeBMW · July 7

On 6/23/2024 at 9:52 AM, J OBrien said:

You

I just bought a 2023 Silverado 1500 High Country 5.3 (L84) with 10 speed (MHS) 4x4. It shakes, shutters or vibrates from start through all gears at any speed! $75,000 truck! Help! John OBrien

For your 2023, try asking here:
https://www.gm-trucks.com/forums/forum/240-2020-2024-silverado-hd-sierra-hd/

Quili · October 30

I have a 2019 Chevy Silverado trail boss with the same problem. Any suggestions on what I need to do? I already had the transmission flushed like last week but it still has a vibration feel to it.

Edited October 30 by Quili