2012 Tahoe LT active fuel management issue

[swathdiver]

4 hours ago, Drakecloude96 said:

Okay. I had a break at work so I took it for a drive. It was kinda hard to tell, the slip was kinda all over. Maybe because I didn't have cruise on, so I was speeding up and slowing down. However I did some reading and saw that one thing to test is the slip speed in gear but not moving and it should be almost 0. Is that true? Mine was 500

Normal slip speed is 10-20 rpms depending on gear and speed.  500 tells us the converter is not locked up, it's slipping.

[Drakecloude96]

1 minute ago, swathdiver said:

Normal slip speed is 10-20 rpms depending on gear and speed.  500 tells us the converter is not locked up, it's slipping.

So new TC? Or solenoids and fluid change?

[newdude]

4 hours ago, Drakecloude96 said:

Okay. I had a break at work so I took it for a drive. It was kinda hard to tell, the slip was kinda all over. Maybe because I didn't have cruise on, so I was speeding up and slowing down. However I did some reading and saw that one thing to test is the slip speed in gear but not moving and it should be almost 0. Is that true? Mine was 500

 

 

Not moving there should be no lockup.  If it was locked you'd stall right out, so 500rpm at a standstill sounds about normal in Drive.  The TC is not engaged.  If you are seeing 500rpm slip while driving steady state so crusing on the highway?  Converter isn't locking up like it should be and you should be seeing a CEL and P0741 or some other torque converter clutch code.  

 

You want to monitor it driving, steady state cruising.  In and out of AFM you may see it bump a bit which I believe is normal as GM uses the TCC to buffer the V8-V4-V8 transitions.  Try driving around in M5 and M6 with the shifter and watch your TCC slip during steady state cruising.  

Edited October 12, 2023 by newdude

[Drakecloude96]

Thank you. I will check that again and try to keep a better eye on it. Now, if it has more than the 20 rpm slip would you do a fluid change and maybe some dr shudder? If its more than 100 Rpm slip, would you do a valve body rebuild and solenoids? Or TC? Just trying to plan my next moves

[newdude]

19 hours ago, Drakecloude96 said:

Thank you. I will check that again and try to keep a better eye on it. Now, if it has more than the 20 rpm slip would you do a fluid change and maybe some dr shudder? If its more than 100 Rpm slip, would you do a valve body rebuild and solenoids? Or TC? Just trying to plan my next moves

 

 

If its not bad so not past 60rpm repeating then sure try fluid first.  If you see high slip, at a minimum its the torque converter.  If its doing it really bad or has been for quite some time, may need a new pump and some other internals like the TCM/Valve body assembly depending on how much TC clutch debris has been pumped throughout.  They can shudder/slip without setting a TCC code too, won't always get a code for it.  

[Drakecloude96]

I monitored it the best I could. I saw anywhere from 30 to 80 in the slip. A few times over that but mostly within that range

[Drakecloude96]

I did a fluid and filter change and added some Dr shudder. It seems better but definitely not gone. I added some pictures of what I found in the pan.

[Drakecloude96]

[Drakecloude96]

I believe I have determined it is the torque converter. I heard putting it in tow mode doesn't let the torque lock up. So I tried it and bam, no more shudder. So I have a billet heavy duty TC on the way and will run it in tow until it gets here. After winter I will also rebuild the valve body just as reassurance. For now I will update you when the TC is installed. Thank you for all the help guys.

[swathdiver]

That's not true.  If the converter did not lock up while towing the fluid temperatures would soar!  That is clutch material in the pan.  Stop driving the truck lest more damage be done.  Remember, all that crap is going through the pump and scoring up the aluminum and eating away at the solenoids.  

 

It may take 24+ quarts of fluid to get most of that out and be sure to have a shop flow test the transmission cooler and lines to make sure they're not restricted.

[Drakecloude96]

Tc is installed and no more shudder. I will definitely be doing a complete flush and rebuild on the valve body just because of all the material in there. But at least the main problem is resolved