Vibration at 25 MPH slowing down

taps929 · January 29, 2018

My 18 does the same thing. I had a 14 with the highway vibe problem. They shimmed my pinion angle and traded the highway vibe for the accel and decel shudder. Told them to take them out, and it went away. But the highway vibe came back. I looked under my '18 and it seems they come out shimmed. I'm wondering if that what it is.

Ducatiden · March 20, 2018

I have same problem,shudder while braking starts at 27MPH and ends at 23MPH. This condition happens while in gear, not in neutral. Notice same shudder while coasting down no brake, however gone in neutral. Had shop foreman ride along he noticed shudder condition. Set up appointment for following Monday. Service report stated no codes, software up-to-date ,no problem found??? Contacted GM have case number waiting for further info or direction from GM!? Tick tock. Truck is new Silverado 1500 WT 6 cyl. 6 speed stock,currently 2k miles on truck.

Ducatiden · March 20, 2018

Update, got a call from &GM today rep. asked if I had returned to dealer? I had not so I said I would today. Interesting I loaded up about 400# set between tail gate and axel, the shudder went away, as soon as I unloaded the shudder came back. Mentioned this condition when I stop at dealer after my trip today they said we might have to wait for a software update from GM. I know the service manager haveing bought a number of vehicles over the years. BTW the GM rep. offered me either a free $100 sertificate for future use at dealer ship or one year free onstar-- took onstair. Good thing truck is totally usable other wise mager downer. Also updated GM rep on above change while loaded and empty.

Edited March 20, 2018 by Ducatiden
spelling

CrowndLegend · March 21, 2018

9 hours ago, Ducatiden said:

Update, got a call from &GM today rep. asked if I had returned to dealer? I had not so I said I would today. Interesting I loaded up about 400# set between tail gate and axel, the shudder went away, as soon as I unloaded the shudder came back. Mentioned this condition when I stop at dealer after my trip today they said we might have to wait for a software update from GM. I know the service manager haveing bought a number of vehicles over the years. BTW the GM rep. offered me either a free $100 sertificate for future use at dealer ship or one year free onstar-- took onstair. Good thing truck is totally usable other wise mager downer. Also updated GM rep on above change while loaded and empty.

I had the same problem when the gas tank was empty, fill the tank full and vibration goes away. I had the dealer replace rear shocks and that lasted 1000 miles, then put some kyb shocks on and it’s a huge difference. Next im gonna replace the front struts for I have a vibration in steering wheel which I suspect is the crappy front struts. Gm really cheaped out on suspension for these trucks.

Ducatiden · March 23, 2018

Update GM rep. emailed, wants me to set up for a complete diagnostic at the dealership. Have appointment for Tuesday 3-27. Hope Mother GM (customer care)comes up with a fix. Tick tock.

Ducatiden · March 28, 2018

Brought truck in Monday by end of day with GM tech support help now think problem is pinion angle, ordered shim kit and will install Wednesday. The shop foreman did drive a comparable 18 truck and fonud same shudder only hardly noticeable. Maybe GM has aproblem here me thinks.

Ducatiden · March 29, 2018

The shudder is gone. After looking at pinion angle front was 2.5 and rear 5.5-- spec is 4 degrees max. They ordered a 2 degree wedge kit. By inserting wedge between spring and axel block the angle was corrected. kit #23469809 qty 2, description shim kit 7.518 N.

Happy to say shudder is gone. Dave the shop foreman said shimming was common on GM back in the 80's. Part of the problem for me was the long box std. cab. Hope this help someone else.

Colossus · March 30, 2018

Glad you have it resolved, here's to many happy trouble free miles..

deputy · May 9, 2018

I have the same problem with my 2016 CC short box.

Last time I took it to the dealer they drove it and of course they couldn't find anything wrong.

Gm rep some help.

B R A D · May 9, 2018

I have the same problem with my 2016 CC short box.
Last time I took it to the dealer they drove it and of course they couldn't find anything wrong.
Gm rep some help.

Watch and see if your rpm gauge jumps a bit while it's doing this. Mine had the same issue and they flushed the transmission 2x and so far so good.

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Kelloggs67 · July 27, 2018

I see that The fix they did worked but I had a 14 in the shop a few weeks ago and the transfer case was making the same thing happen if you put it in 2 WD it would stop in if you had it in auto or four high it would shake

Instructor31 · November 23, 2018

did you install a lift kit on your truck? Some people will install the rear blocks incorrectly and the angle that the rear diff is supposed to be with the drive shaft will be off and will cause vibrations at those speeds.

isalas · June 17, 2019

This was my issue...fluid...yes FLUID.

No more shake/shudder in my 17 Denali.

https://ww7.oemdtc.com/8737/shake-and-or-shudder-during-light-throttle-acceleration-between-25-and-80-mph-40-and-128-km-h-at-a-steady-state-2015-2018-cadillac-chevrolet-gmc

manderson7015 · July 22, 2019

Weird i'm having same issue in my 18 z71. I thought the road was bad but it did it in the walmart parking lot the other day. Like you are going over rumble strips.

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