Worn out Motor Mounts

Gangly · November 13, 2023

While paying for having had the transmission serviced in my 2020 5.3 with approximately 115k miles on it, the dealership service writer proceeds to tell me that both motor mounts are bad and that they need to be replaced. For an estimated cost of approximately $1,600 dollars, the dealership can proceed with the work and get my truck back on the road for me. I kindly decline the services offered, hop in my truck and drive home.

Once I got home, I lifted the hood and observed the engine while running and it is not shaking or vibrating. I hear no clunking when accelerating, and I have no vibrations from the driveline while driving it. I tried to look at the motor mounts to identify torn sections of the polymer, damaged or shifted bolts, or anything else but my view was limited. I'll put it on the lift in the next few days to get a better look but as of right now I have not identified anything obvious that would say I have broken motor mounts.

Has anybody else experienced broken motor mounts on their T1? Have any of your replaced them on your T1? Though I own, and have worked on, heavily modified vehicles with significant engine modifications, I don't recall ever having to replace motor mounts on any of my vehicles due to deterioration, damage, etc. and 115k miles on a truck seems like an awful short amount of time and mileage to be experiencing this issue.

Any thoughts?

Bikerjon · November 14, 2023

I have not had motor mount failure on a T1. Back in the day we would brake lock the wheels and use the engine to torque the driveline forward and in reverse. That should should reveal loose or broken mounts.

Let us know your findings.

AJMBLAZER · November 14, 2023

See if you can get a breaker bar between sides of the motor mounts…but not sure if there’s space for that.

silveradosid · November 14, 2023

the k2's have a tsb about ground out and gm had a revised mount for them, i would assume 2020 and newer mounts would be the updated mounts. look at the mounts and see if there are any wet spots around them, they have a liquid in them that sometimes leaks out

newdude · November 14, 2023

K2s ate up mounts a fair bit, especially NYS Trooper Tahoes. Haven't seen any get replaced on T1s yet though. I do see however a fair amount in stock at dealers in the US so...perhaps they wear them out? GM has them backordered too.

Edited November 14, 2023 by newdude

Gangly · November 14, 2023

Thanks for all the help and insight guys, I appreciate it. I'll take a closer look at the mounts and try to see if I can identify any tears or liquid seepage. I'll also have my wife put a load on the engine while in the driveway so I can observe for any abnormal rising or rotating of the engine.

From what I have observed online, its a fairly easy job to change the engine mounts. I just need to remove the steering linkage, the exhaust manifolds and the oil dip stick tube to access and remove the mounts. I'll probably replace the spark plugs while I'm at it since I have to pull the plug wires anyways to remove the manifolds.

silveradosid · November 15, 2023

that's a lot of labor for just to change a engine mount, make me think getting the 2.7 wasn't such a bad idea after all

Gangly · November 15, 2023

5 hours ago, silveradosid said:

that's a lot of labor for just to change a engine mount, make me think getting the 2.7 wasn't such a bad idea after all

In reality, its about 2.0 hours per side, which isn't that bad. I also believe I am in a one-off situation as I haven't seen or heard of anybody else experiencing this yet.

However, newdude's post has me thinking that it might be starting to occur and we just haven't heard much about it yet.

Silverado Mann · June 30, 2025

21 lt trail boss 5.3.

Completely leaked out mounts, bilaterally. Shaking, shuddering, jerking. Most noticeable at lower speeds, and in every single gear including neutral and park. Dealer continues to ignore and state truck runs just fine, and that is normal. At 57k mileage. Powertrain still covers, but they refuse to admit there is an issue. I've already just recently had a granny flush and oil and filter change.Fuel and motor treatments from dealer as well and plugs and wires swapped out. I've run out of options here. Please help.

Bikerjon · June 30, 2025

1 hour ago, Silverado Mann said:

21 lt trail boss 5.3.

Completely leaked out mounts, bilaterally. Shaking, shuddering, jerking. Most noticeable at lower speeds, and in every single gear including neutral and park. Dealer continues to ignore and state truck runs just fine, and that is normal. At 57k mileage. Powertrain still covers, but they refuse to admit there is an issue. I've already just recently had a granny flush and oil and filter change.Fuel and motor treatments from dealer as well and plugs and wires swapped out. I've run out of options here. Please help.

I think you need to go to a different dealer and talk to the Service Mananger.