2014 Silverado TCC lockup

[Obsolete489]

I have a completely stock truck with a l83 and 6l80e, and was wondering about making the torque converter fully lock in 5th and 6th gear. So set desired slip set at zero and raise the error ramp so it applies more pressure to keep it there.

Is the a bad idea for some reason with a stock converter? Not worth doing? Any input is appreciated.

[LSChev]

The way I understand it, the stock settings are set at 10slip because the ECU wants to apply just enough pressure to keep the clutch engaged but not so much pressure that it takes a long time for the clutch to disengage when commanded. I have changed the settings to correct cruising issues with heavily modified vehicles but I have not seen any issues or benefits with stock.

[tek1229]

I was taught that GM wants it slipping just a little to help with the customer feeling the engine firing vibrations.. Same reason a clutch plate has those springs, to help dampen vibration..

Personally I changed my slip speed to zero on my 2013 to help save my torque converter, hasn't been an issue yet, been that way about 6 months.. The 8 speeds are having converter issues big time, Guess there is a 'big fix' in the works for those, we're not supposed to replace the converters anymore until the fix comes out, hopefully in Janurary.. 6 speeds not so much, but they do have some problems with chattering/wearing out..

[Obsolete489]

So, it won't hurt anything setting it to zero slip? To me that would seem to be the best for the health of the converter but I wanted to make sure there wasn't something I was missing.

[Obsolete489]

Sunday bump, anyone else try messing with their TCC settings? I did try changing mine and nothing feels abnormal.

[1slow1500]

Mine are so changed that that the tires spin 3-4 times before tcc kicks in.

[Obsolete489]

So you fully lock almost immediately? Command zero slip?

[kevin87turbot]

I zero the TCC slippage tables on all of the 6L80E applications. So far, it seems to help. My neighbor owns a transmission shop and was having way too many 6L80 torque converters go out. This seems to have helped his returns significantly.

[IARLLC]

Is this only on trucks that have disabled AFM/DOD?

[Obsolete489]

Thanks Kevin87.

IARLLC, are you wondering if the increased desired slip for DOD is what is causing that, if they were indeed DOD trucks with the issues?

If it is constantly bouncing between v4 and v8 I could see that being an issue.

[IARLLC]

I have heard a lot of these complaints about the TCC on the 8 speed and read the TSBs. I usually seriously reduce converter slippage on GEN3 and GEN4 if non-AFM/DOD.

If I recall the TCC is set to slip a lot more in V4 mode to smooth out the pulsations and maybe to keep from bogging too much. So I was wondering if people who are zeroing TCC tables are just doing it in V8 mode only or only on rigs that disabled the AFM/DOD. That is my reason for the question. Sorry I was not clearer.

[Obsolete489]

I was wondering about that in v4 mode, and for that reason I haven't completely locked it in v4 yet, just reduced it. It does make me contemplate shutting off dod.

[IARLLC]

Kinda off subject but related to DOD...disabling

GM had quite a few issues with the DOD lifters. Early on, they blamed the oil manifold. From what I have seen I think that they were right. An early 2015 L86 broke #7 intake valve spring and suffered light valve contact (heavy valve, heavy DOD lifter, weak springs used until mid-2015). Under GM's TSB it got all new DOD lifters and a new #7 intake valve and spring and new intake manifold. Client refused the GM recommended new oil manifold at the time. 2 years later (of constant high rpm) it hammered #7 intake lifter and lobe. New cam and lifter....lifter made it 3 hours. New oil manifold (and another lifter) and all OK for 6 more months (knocking on wood now). Heard the story several times...Turning off DOD helps with a few other complaints (oil consumption, carbon build-up) but I cannot confirm that it reduces valve-train issues. It kind of makes sense since there are oil manifold issues that disabling the function could reduce oil starvation to the lifters....but read below.

I mention the springs as well as I have now seen 3 2015 L86 brake intake valve springs (melts the intake runner every time) with DOD disabled....later realized that GM upgraded the springs (from yellow to blue) during 2015.

[Obsolete489]

Kinda off subject but related to DOD...disabling

GM had quite a few issues with the DOD lifters. Early on, they blamed the oil manifold. From what I have seen I think that they were right. An early 2015 L86 broke #7 intake valve spring and suffered light valve contact (heavy valve, heavy DOD lifter, weak springs used until mid-2015). Under GM's TSB it got all new DOD lifters and a new #7 intake valve and spring and new intake manifold. Client refused the GM recommended new oil manifold at the time. 2 years later (of constant high rpm) it hammered #7 intake lifter and lobe. New cam and lifter....lifter made it 3 hours. New oil manifold (and another lifter) and all OK for 6 more months (knocking on wood now). Heard the story several times...Turning off DOD helps with a few other complaints (oil consumption, carbon build-up) but I cannot confirm that it reduces valve-train issues. It kind of makes sense since there are oil manifold issues that disabling the function could reduce oil starvation to the lifters....but read below.

I mention the springs as well as I have now seen 3 2015 L86 brake intake valve springs (melts the intake runner every time) with DOD disabled....later realized that GM upgraded the springs (from yellow to blue) during 2015.

Interesting.. So longish story short, you'd recommend disabling DOD if you have a pre-2015 truck? I go back and forth on whether or not I even care for it. It does help with light cruising/ in town economy but it is also kinda annoying as the transitions can be a bit funky. Maybe I'll try disabling it and see what that does to my mileage for a tank or two.

I really don't mind being off subject, I like hearing info like this, so thank you for the input.

[IARLLC]

I turn it off first thing on any year DOD rig, 4th or 5th GEN. There are enough reasons as far as I can tell. Maybe with the newest set-up it will be a better option. I have not looked at it well enough yet but since the newest one seems to have very accurate control over all cylinders it might not cause as much issue (serious carbon build-up on 4 ports/valves, oil usage even pooling during V4, not to mention strange, sometimes illogical valve-train fatigue). Since GM recommended a newer part number for the oil manifold maybe they actually resolved the oil control issues. I guess we will see sooner or later.

[Obsolete489]

Well for the time being I think I'm going to follow suit and disable it, the potential issues aren't worth a little gas.

Thanks for all the input/help.

[IARLLC]

You are always helping guys. I am just glad if I have something to offer.

[Obsolete489]

Little bit of an update, in light cruising where it would normally go into v4 mode where I now run v8 I really see no difference in instant mileage on the scanner, its certainly close enough to the same to be well worth the benefits of shutting off dod.

As a side question, have any of you guys tuned the l83? I've been working on mine for quite awhile now and I'm happy with it overall, but it seems like I have to run an absurdly low timing at low rpm. Anything north of .5 g airmass and below 1600 rpm I'm between 10-15 degrees of timing on e85 and that will kick up kr sometimes. I've seen timing get hammered all the way down into the low single digits because of knock learn at times.

I realize these things are high cr so maybe this is just the way it is, just want some input from anyone else that's tuned one of these.

The is in a complete stock 4 door 1500 by the way.

[IARLLC]

Lots of L86 but no L83 yet. On the L86 I don't take try to eliminate KR but for race trucks that will see high temps, lugging through sand, and I do reduce a little timing in the areas that get constant KR. Cold Air Intake helps a bit with that especially during long idle warm under hood temps but you know that. The higher speed open road L86s can use a decent bit of timing....especially without the cats I am surprised that you are even getting KR with E85. Maybe it doesn't get the PE in quite as quickly as it could use it?

Quick reminder about the carbon build-up that these DI rigs can get... Maybe a top engine clean every so often will reduce the KR. Curious what others are doing.

I am sure some others on here have better advice specific to the L83.

[Obsolete489]

I may have to start a different thread just to get a little more traction on that topic specifically.

Thanks for the input nonetheless, it is still useful. From 1200 to 1600 I had remove 6-10 degrees from the e85 adder above .52 airmass, when comparing to stock.

It makes me wonder sometimes if I should just run a little more timing and let the knock sensors sort it out, but idk. It's not like its constant kr, usually just little blips of a degree or two here and there but occasionally it will spike to 6 or so degrees. One thing to note, some of these spikes(but not all) do show up immediately following shifts, so its possible its false?

When you say top engine clean.. do you mean rip everything apart and go to town cleaning? This thing does have 100k on it, so there could be something to that.