Loud rear end noise when accelerating after being parked

[Katie989]

Hi,

I’ve got a 2015 5.3 litre v8 crew cab Silverado 4X4 with about 70 000 km on it and on 3 occasions there has been a loud bang coming from the rear of the truck when pressing the gas pedal to take off (after being parked). It’s only ever done it after being parked for a couple hours or overnight. Doesn’t do it when driving around stopping at stop signs or stoplights. Thought it was  ice and snow build up at first because we have had mild then cold weather, but this morning when I pressed the gas the truck didn’t even try to move, which was followed by another bang and then the truck was fine. Only thing different I noticed afterwords was a very slight vibration on a section of road where there was no vibration before (but roads are kinda rough here, it’s hard to tell between road and truck vibration). 
 

The stupid truck was in the shop for an inspection 3 months ago so it’s not like I’ve been neglecting it. 
 

I’m trying to figure out what it could be in order to make the best call on whether or not to park it until I can get it in to get it looked at, which will probably be a week or 2. I’ve done a lot of googleing but can’t find anything making a loud bang-mostly just clunks. I don’t consider this noise a clunk at all. It makes my dog get up from laying down. It’s comparable to the decibel your vehicle makes when you hit a huge pothole and your first thought is oh ****. I had my previous truck until it was 10 years old and it had its share of clunks, whines and rattles but nothing like this. 

Have you had issues with the infamous driveline clunks, worn u joints, binding slip yoke, or broken rear diff parts? Have any of them sounded this loud? 
I got distracted from this post for a bit and was doing more googleing. Found 2 post suggesting it’s the rear diff. Not good. Any thoughts? 

[davester]

Did you leave the truck in 4x4 mode (so perhaps the drivetrain was bound up when you stopped)?

[Lsgun1]

Is a rear brake caliper locking up? Have you looked at anything?

[JimCost2014]

Torque converter or stator shaft, both common problems in the early years (14-15).

[L86 All Terrain]

11 hours ago, JimCost2014 said:

Torque converter or stator shaft, both common problems in the early years (14-15).

This. Had a TC replaced on my 8L90e then shortly after had the whole trans replaced.

 

It is a delayed engagement right? You shift into reverse or drive and about 2 seconds later it slams into gear then is fine when the trans is warmed up? 

 

This is only for the 8spd trans though I believe, not the 6 speed. Not sure which transmission you have. Here is the TSB to take to GM. Get in there quick hopefully you still have some powertrain warranty. https://static.nhtsa.gov/odi/tsbs/2016/SB-10097193-2280.pdf

[Katie989]

On 1/30/2020 at 3:33 AM, davester said:

Did you leave the truck in 4x4 mode (so perhaps the drivetrain was bound up when you stopped)?

This is a definite possibility. I know 2 of the three times I had used the 4x4 right before shutting the truck off (got stuck in a parking lot and in the driveway!)

[Katie989]

On 1/30/2020 at 8:57 AM, Lsgun1 said:

Is a rear brake caliper locking up? Have you looked at anything?

I’m having a local mechanic take a look at it soon and they think it has to do with the rear brakes too. I’m not convinced but hoping that is what it is. They do squeak when the truck is first used but the dealership just inspected them and replaced a caliper on the one side 3 months ago tho. 

[Katie989]

 

19 hours ago, JimCost2014 said:

Torque converter or stator shaft, both common problems in the early years (14-15).

 

8 hours ago, L86 All Terrain said:

This. Had a TC replaced on my 8L90e then shortly after had the whole trans replaced.

 

It is a delayed engagement right? You shift into reverse or drive and about 2 seconds later it slams into gear then is fine when the trans is warmed up? 

 

This is only for the 8spd trans though I believe, not the 6 speed. Not sure which transmission you have. Here is the TSB to take to GM. Get in there quick hopefully you still have some powertrain warranty. https://static.nhtsa.gov/odi/tsbs/2016/SB-10097193-2280.pdf

Oh wow what a nightmare! Mines a 6 speed so this isn’t the issue but thanks for the info! The symptoms sound similar but I’m under the impression that pressing the gas pedal has something to do with causing the bang. 
I’d have to wait 20 days to get it into the dealership so I’m having a local mechanic look at it soon (and keeping the dealership appointment just in case). Hopefully the bang just has more bark than bite. 

[JimCost2014]

31 minutes ago, Katie989 said:

 

 

Oh wow what a nightmare! Mines a 6 speed so this isn’t the issue but thanks for the info! The symptoms sound similar but I’m under the impression that pressing the gas pedal has something to do with causing the bang. 
I’d have to wait 20 days to get it into the dealership so I’m having a local mechanic look at it soon (and keeping the dealership appointment just in case). Hopefully the bang just has more bark than bite. 

Our 16 Tahoe has the 6 speed and we had the torque converter replaced in it last summer.