Complete Guide to Tuning the 6L80E Transmission - Part 5 TCC Lock Up

Let's talk about locking and unlocking the TCC (torque converter clutch).
No files for this video, but here is the link in case you missed it previously.
Google Drive:
drive.google.com/open?id=12tz...

[@treybadd]

I’ve seen countless other channels saying increase the TCC apply rate. It clearly says “rate”. So a smaller number makes faster rate. SIU automotive did extensive tests and thought you would increase that value and get more pressure. His test actually showed it went slower with less pressure after he increased all values right of zero. I lowered mine. Thank you.

[@teagreen2220]

Remember those old transmissions that didn’t use a lockup converter? They were wonderful for so many years and miles. A lot of new technology is not very reliable IMHO and for myself it is unnecessary. The amount of energy saved by a lockup converter doesn’t even come close to covering the amount of energy spent replacing a blown transmission while you own the vehicle. I prefer it old school with no lockup, lasts pretty well!

[@leftyeh6495]

umm, my 6l90e in my 7000lb truck lasted 315,000 miles. A vehicle old enough to not have lock-up would have needed at least 3 engine and trans rebuilds by now.

[@PHLTHS]

Also there is 2x key pieces of information that is missing here. The TCC Regulator Offset & Gain values. Looks like are not avalaible to be edited in this OS. These values control the initial PSI that is applied to the TCC before the Apply Ramp Table is then used to then finish off with the TCC Desired Pressure Table.

[@jeromebeaudoin6246]

Great info as always 💪

[@SilverSurfer77]

Thank you brother!

[@LSAGT]

Hello, I did this and it has helped my TCC lock up tremendously. I have a circle D and it used to jolt my car both when lockds up and unlock. However now I kind of feel a slight shudder when it locks up .

[@PHLTHS]

I have played with enabling Shift Lock. You are correct it does leave the TCC locked during gear changes. Whlist it isn't too bad during upshifts as you can control the torque management etc, the downshifts feel very harsh if you have enough pressure to keep the TCC locked without slipping. If there is slippage happening, then the downshifts are not harsh at all. I've been trying to figure out how to log or calculate what the PCA Pressure values as so I can map out where in the TCC Desired table I'm using but haven't had any luck so far. Also great info on the TCC Apply Table.

[@SilverSurfer77]

Thank you for the real world experience on the shift lock enable part! Curious about PCA vs PCS. PCS is pressure control solenoid, but what exactly is PCA? The HPT scanner is pretty limited in the pressures it can log for the trans. I appreciate any info you are able to dig up and share. Thanks!

[@PHLTHS]

@@SilverSurfer77 there is one post that I suspect may be the equation. TCC Line Pressure] = [TCC Regulator Gain] * [TCC PCS Pressure] - [TCC Regulator Offset] or solving for PCS Pressure: [TCC PCS Pressure] = ( [TCC Line Pressure] + [TCC Regulator Offset] ) / [TCC Regulator Gain] But I haven’t confirmed if they mean PCA not PCS.

[@BigEbikesports]

Only Gm can screw up a wet dream! They make some of the best engines minus the AFM/DOD junk they put in them. The transmissions are nightmare to tune especially trying to decipher which operating systems won't pulse the TCC. Even if you get the TCC to lock with enough pressure, it makes shifting hard and abupt trying to unlock. Then there is the AC on even if programmed to 0 slip, it will still be a minimun of 4.5rpms slip. I have a circle D twin disk in my gen V Silverado l83 and circle D claims no tuning required which is total BS because the TCC will shudder and fishbite until it grenades with stock tune. I finally just said F it and made all my slip tables to 20rpms slip. Been running like that for the last 40,000 miles and so far so good. Did a fluid/filter change at 30k on converter and no issues. Fingers crossed!

[@darkzero6282]

Excellent information. Now we need some advice about how to tune the idle after a big cam install. Your methods are always spot on :).

[@SilverSurfer77]

Thank you for the kind words! I have thought about doing an idle video...

[@linliu7125]

Quite helpful! That tcc apply ramp table is indeed misleading!

[@isidrosevier1125]

I also have a single disk high stall and circle d told me to lock up in 5th at cruising and not to lock up at all at wot. Seems to work pretty well just cruising around.

[@treybadd]

Lower gain on regulator and offset are holding TCC slip closer to zero than increasing. I’m trying different settings.

[@SilverSurfer77]

My OS does not offer access to gain and offset.

[@treybadd]

@@SilverSurfer77hmmm well I just downloaded the latest a couple weeks ago and a mpvI3. Maybe time to update…

[@Bmloww325ie36]

im doing 14 silverado 5.3/6l80 & it has the shift lock enabled on the factory calibration

[@SilverSurfer77]

Thank you for letting me know sir!

[@SilverSurfer77]

I wonder if this is one of the reasons why the truck converters fail?

[@rookiechevey]

I'm tuning my 2014 Siverado 1500 5.3/6l80 and my shift lock is disabled on the factory calibration.

[@SilverSurfer77]

@@rookiechevey whoa that is interesting...I wonder if the enable/disable has to do with options, like rear gear or towing package?

[@rookiechevey]

@@SilverSurfer77 I have since tuned a 2016 and 2017 Silverado 1500 and they also had shift lock disabled from the factory.

[@treybadd]

I ended up locking in 4-6. Command zero slip.

[@SilverSurfer77]

You crazy! I've been thinking about doing 6th only.

[@treybadd]

@@SilverSurfer77 lots of 35 mph city driving. It’s a daily I want to keep pretty tame but borderline sporty.