Looking at a 2015 GMC Sierra 1500 SLE, what issues to look for?

[No Tyme]

Found a 2015 GMC Sierra 1500 SLE that I am interested in. Has the 5.3 Eco Tech 3 engine. Pretty much the same motor that my 14 Silverado had (I believe). Just under 85K on the clock and it has everything I am looking for.

Any input would be helpful.

[steelerdude15]

There are a few things to look for. If you can, check the transmission fluid level and condition. If it smells burnt and is dark brown or black, I’d walk away from it because it’s only a matter of time before the transmission goes. I’d also look at the transmission fluid temp in the DIC to see if the pill has been flipped or deleted. If it the temp gets to 190 F, then it hasn’t been done.

 

Go over bumps at very slow speeds to see if you hear any clunking coming from the rear. If you do, the leaf spring pads are shot. GM came out with redesigned pads, but they don’t make a difference.

 

If you can, get up to 80 mph to check for Chevy shake. You’ll feel the truck shake. Some here have said it’s like going over rumble strips, but videos on YouTube make it seems like it’s worse than that. If it has it, look for something else.

Take time to play with the radio to make sure it doesn’t start acting odd. For its not responsive or starts doing things on its own, the screen might have to be replaced.

 

Run the ac to make sure it cools. The ac compressors are known to fail due to a bad weld.

 

I’m not sure if this was fixed for the 15 MY, but if it has 4WD, put it in each mode to make sure everything works. There was an issue on 14s where the trucks wouldn’t go back into 2WD after the truck was shut off while still in 4WD. I think an update fixed that.

 

Of course check for recalls, a Carfax report, and service records if they have them.

[OffTheAir]

Adding on to the service records, I would also keep an eye out for any sort of radiator work that was performed. The radiator and cooling lines leaking is a fairly common issue as well, and it is not a fun repair. If you happen to find that this issue has already been taken care of, that will be a huge plus!

[No Tyme]

Thanks for all the info. Didn't get the 15 Sierra, instead got a 18 Silverado 4X4 Crew

[pokismoki]

14=15 years had leaky AC systems, and trans vibes the 18 years will cost lots of money to unlock the ecu/tcu

Edited May 1, 2022 by pokismoki

[No Tyme]

16 hours ago, pokismoki said:

14=15 years had leaky AC systems, and trans vibes the 18 years will cost lots of money to unlock the ecu/tcu

I don't plan on doing any tuning to the motor so is that where you are going with  the "unlock the ecu/tcu"? I did Black Bear tunes to the 14 but going to spend my happy money now on my Harley.

[JimCost2014]

On 4/27/2022 at 5:32 PM, No Tyme said:

Thanks for all the info. Didn't get the 15 Sierra, instead got a 18 Silverado 4X4 Crew

You will like the 18, seems like that was the year most all of the bugs had been worked out.

 

Really like mine, been virtually trouble free since the day I bought it.

[Gagliano7]

On 5/1/2022 at 1:12 AM, pokismoki said:

14=15 years had leaky AC systems, and trans vibes the 18 years will cost lots of money to unlock the ecu/tcu

The ecu is easy to unlock on the 18 but it is the tcu that you have to send in to have unlocked.

[No Tyme]

I did a Black Bear tune on my 14, mostly for the transmission. I don't plan on doing any mods to the engine in my 18. I guess that is a sign of me getting old LOL, but looking more for longevity out of the truck.

Concentrating on service and upkeep for the time being, but did find a set of Hollander 5330's for it. Luv the look of those accessories wheels. 

[newdude]

2 minutes ago, No Tyme said:

I did a Black Bear tune on my 14, mostly for the transmission. I don't plan on doing any mods to the engine in my 18. I guess that is a sign of me getting old LOL, but looking more for longevity out of the truck.

 

 

 

If its a 6 speed change out the transmission thermostat for the new GM lower temp one.  86774933 and 23135703.

[LDM]

2 hours ago, Gagliano7 said:

The ecu is easy to unlock on the 18 but it is the tcu that you have to send in to have unlocked.

That only applies to the 8 speed transmission with the T87A controller for 2017+.  The 6 speed still uses the regular T43 controller thru 2018.  In 2019 they switched to the E90 controller (I believe, not 100% sure on this) for both the 6 and 8 speeds, which I don't believe is even able to be unlocked yet.

[No Tyme]

 

I was just looking at that yesterday and I am still trying to understand if I need new O rings when I do this. One video I seen said yes.

What is your thoughts?

Edited August 5, 2022 by No Tyme

[mikeyk101]

I suppose that is the "proper" way to do it but I say it's up to you. I was never able to find a GM part number for those o-rings. I have had those lines off twice, first to do pill flip and second to change to new thermostat. I am still using the original o-rings and no leaks. 

 

But pay close attention to those. They are tiny and easy to lose, I did discover that unfortunately...

Edited August 5, 2022 by mikeyk101

[16LT4]

I’ve also reused the orings through a pill flip and subsequent T stat change. More than losing them, make sure they’re not stuck in place and get damaged. Basically, just keep track of them.

[No Tyme]

Completed the Pill Flip yesterday and I believe I lost a couple of tables spoons of fluid if that. I did check trans fluid and it seems low, with temp about 100 degrees and just having the transmission flushed at the dealer a month ago I would think it would at least be in the safe range... ended up just below it.

I will check again and if the level remains below the safe range I may add a bit to bring it up.