4L80 lockup help!

[tomrog123]

Hello,

After a few days of scouring the forums with no avail, I figured id post and try and get some help.

I have a 6.0/4L80 swapped 99 k1500 suburban. P01/0411 ecu PSI harness. Engine is a LQ4 milled 862 heads (roughly 11:1 cr) small summit stg 2 truck cam and a WARR 92mm DBC TB. trans came out of a 2001 or 2002 2500 and I'm using the ecu from that truck. trans is fresh-ish rebuilt with about 4k miles. with an Atlantic Coast Converters maxed out stock converter (roughly 3k stall speed)

The issue is lockup is wonky after swapping the 6.0 in (I swapped a 5.3 in back in March 2021) Typically if it locks up it will do it once the first time it hits lockup parameters (55mph) the issue is it wont go back into lockup after that, or it will fall out of lockup, or just flat out wont lockup at all. This was not an issue with the 5.3

I can manually command lockup via the scanner and duty cycle shows 100% (the rare occasion it does lock up it shows 99.2%), I also get a random misfire intermittently (no change in engine operation runs smooth) I've tried a number of different things but ill post the tune and some logs. I hope this is something simple, i really dont want to make a 7 hr drive without lockup. Thanks in advance guys!

12-21-21 lockup fix 4.hpt12-22-21 trans lockup log 1.hpl12-22-21 trans lockup log 2.hpl12-22-21 trans lockup log 3.hpl

[tomrog123]

Also no transmission related codes what so ever, shifts as advertised and lockup when it happens (automatically or commanded) is crisp.

[blindsquirrel]

What's different in the tune file between now and when it last worked?

[RDF1]

Disable P0300 and max out the missfire tables.. Give that a try and see if it will lock and stay locked. its a quick and easy test to see if the PCM is killing TCC because of the misfire.



12-22-21 trans lockup log 3.hpl
In this datalog at Time: 09:39:19.204 TCC Missfire Off states NO..
Time: 09:39:19.214 TCC Missfire Off states Yes.

After that point it looks like its not commanding TCC to lock anymore.

You can clear the codes while driving and if TCC comes back online, then its going to be missfire codes getting you.

[tomrog123]

I did that and it fixed it! Thanks for the help!