2014 4.3 & 6l80

[JHZ71]

The truck is a 2014 with the 4.3 and 6 speed and 163,000 miles. Recently, the truck seems to be consuming 3-4 quarts every 5,000 miles AND the transmission has recently been approaching temperatures of 235-245 under normal driving conditions. Anyone have similar experiences with this? If so, how was it fixed? I was thinking it’s time to get rid of it before I see a 8,000$ repair bill. Or is this considered “normal” for these trucks. Any feedback would Be appreciated. Im driving myself nuts thinking about it 

[CamGTP]

The oil consumption is pretty darn high. Hard to say what is the exact cause without doing some testing. Could be a poor working PCV system or it may be from the AFM system that shuts down 2 cylinders on the freeway.

 

I would be pulling the spark plugs to see what plugs look worse than others to help pin point where the oil is going.

 

The transmission oil temps are really high for normal driving. How old is the fluid?

 

You could be having issues with oil flow in the transmission if the filter is getting plugged up. Or could even be that your transmission thermostat is not working like it should to open at the proper temp to help keep oil temps more normal around 180-190 degrees. If you are handy you can do the thermostat pill flip mod that will open the thermostat 100% of the time to see if that helps bring the temps way down. If even doing that does nothing, then you have bigger problems like a plugged filter or internal slipping that is causing the transmission temps to get really hot.

 

The thermostat mod is free and pretty easy to do if you are up for it.

[JHZ71]

2 minutes ago, CamGTP said:

The oil consumption is pretty darn high. Hard to say what is the exact cause without doing some testing. Could be a poor working PCV system or it may be from the AFM system that shuts down 2 cylinders on the freeway.

 

I would be pulling the spark plugs to see what plugs look worse than others to help pin point where the oil is going.

 

The transmission oil temps are really high for normal driving. How old is the fluid?

 

You could be having issues with oil flow in the transmission if the filter is getting plugged up. Or could even be that your transmission thermostat is not working like it should to open at the proper temp to help keep oil temps more normal around 180-190 degrees. If you are handy you can do the thermostat pill flip mod that will open the thermostat 100% of the time to see if that helps bring the temps way down. If even doing that does nothing, then you have bigger problems like a plugged filter or internal slipping that is causing the transmission temps to get really hot.

 

The thermostat mod is free and pretty easy to do if you are up for it.

Fluid is about 3.5 years old and 50,000 miles on it. Transmission clunks hard from 2nd to 1st. Also slips real bad sometimes too. I’ll look into the transmission mod, thanks for the feedback! 

[CamGTP]

If it's already slipping bad sometimes, it's been on it's way out for a while then. Nothing will really fix the slipping and hard clunk except for a rebuild.

 

You could suck out a quart of fluid and dump a whole bottle of Lucas in it, but that may only do so much.

[JHZ71]

Yea that’s what I figured. Then with the temps getting hotter, and the oil consumption it may be just time to throw the towel in. Thanks again

[Grumpy Bear]

 

As true as it may be that is a very short lifespan for both the motor and transmission. The 6L80E behind a 4.3 is a rare bird in a transmission shop. 

 

https://gearsmagazine.com/magazine/general-motors-6l-family-is-it-normal-or-do-i-have-a-problem/

 

Another member posted this link a day or so ago. Read all the 6L80/90E articles. It will help you in the future...or now if you decide to keep her. 

 

This is an Ecotec3 4.3. They don't suffer the same AFM system root cause oil consumption Vortec V8's do. Mostly breather/baffle issues and dump valve orifice baffle.  IF the AFM is still working I'd guess an educated guess the rings are varnished collapsed and amazed the AFM is working at all. An oil selection and maintenance issue. Yes it could be a PCV issue as well. Easy enough to check. Right? Ever change the PCV valve? 

 

Or junk it but think about how it was maintained. So you don't repeat it. 

 

Keep it cool,

Keep it changed,

Keep it full,

Keep it filtered. 

 

 

[Donstar]

How is the rest of your truck?  Did this high rate of oil consumption or transmission over-heating suddenly occur?  It sounds like you may have avoided/saved a lot of maintenance related costs.  If the truck is in decent shape, it will cost you a lot more to replace it than fix it.  

[JHZ71]

The rest of the truck is fine. This oil consumption started pretty recently. It was not a gradual increase. It was pretty sudden. I did all recommended maintenance according to the owners manual. Just a weird situation

Edited August 19, 2021 by JHZ71

[dieselfan1]

Do the pill flip for the trans. It will run a lot cooler. 

I'd change the fluid too.

Like Cam said I'd be pulling the plugs to start with.

[Grumpy Bear]

2 hours ago, JHZ71 said:

The rest of the truck is fine. This oil consumption started pretty recently. It was not a gradual increase. It was pretty sudden. I did all recommended maintenance according to the owners manual. Just a weird situation

 

I just went through this with a GM 2.4 I4. Nearly 100K miles and never used a drop then a quart in 600. Rings collapsed. Varnish and I too changed oil actually more often than the OEM OLM recommended OCI using Quaker State UD at the call out SAE grade and it sill varnished. 

 

We did the TSB's and it helped but no real joy. Then I did a 5:1 TRIAX S7 over 1500 miles and it cleaned right up and again is using no oil. Yes we had to clean the PCV system and valve covers and valves by hand to get started. 

 

 

Edited August 19, 2021 by Grumpy Bear