I would like to be able to run lockup on my 2005 silverado 2500 hd in 3rd gear but when i leave off my petal to 0% throttle it unlocks.them when I roll back in the throttle it stays unlocked for a little and then locks again. Not sure what table to change to keep lockup on. I searched all over and figured out how to change it for 4th gear but dont know if anything is changable for 3rd. Also is there anything to change to keep lockup on when on the brakes as well.
There are min TCC throttle settings in a lot of OS's but not all. Its in the Torque converter tab usually. Post your tune and I'll show you if you have it.Originally Posted by Nathan Z
Trucks are setup like this BTW. Have no idea why.
There is also a TCC/brake fuse that it could be. The PCM is looking for power while NOT on the brake to enable the TCC. This wire is fused by something called like TCC brake or something along those lines. Check your schematic to know for sure.
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Ok i found the min torque converter settings and then changed then but in third it still unlocks but not fourth gear unless on the brakes!final timing tune1 with shift points changed1.hpt
Try copying the min throttle release out of a car tune file you can download off the repository.
I'd pick the same year car if you could. Vette or camaro.
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Ok thanks for the reply. I will see what happens!
So i tried changing it to the same as a corvette and it does the same as before(i had changed the settings already) so it still is unlocking at 0% throttle any more ideas?
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If your shifter is in 4th gear but transmission is in 3rd gear with TCC locked, when you lift off the throttle your converter is prob still locked but your overrun clutchs arent holding, only the sprag is.
Are you datalogging TCC slip? Status?
Putting this in the trans gives you engine braking in all gears and lets you do what your wanting to do.
Other option is to just the shifter into 3rd so overrun clutchs engage.
https://www.sonnax.com/parts/4496-sm...utch-valve-kit
If your shifter is in 4th gear but transmission is in 3rd gear with TCC locked, when you lift off the throttle your converter is prob still locked but your overrun clutchs arent holding, only the sprag is.
Are you datalogging TCC slip? Status?
Putting this in the trans gives you engine braking in all gears and lets you do what your wanting to do.
Other option is to just the shifter into 3rd so overrun clutchs engage.
https://www.sonnax.com/parts/4496-sm...utch-valve-kit
hey thanks for the info guys i will try more and let you guys know what happened! I think ill try the brake fuse and see what happens it does stay locked in fourth and second gear when at zero throttle but third seems to be the kicker! also i would be in drive!
I was looking for my brake fuse but wasnt able to find it anyone know where it is?
Not sure exactly why you are looking for the brake fuse but it is a 10 amp fuse in the fuse panel under the dash. The fuse even if it was missing completely could not cause your problem, the brake switch is a normally open switch. Why not simply post a log of it doing what you don't like logging the brake switch and all the transmission related PIDs so that we can better help.
Robert Moreau
Technical Sales and Marketing Support Specialist
TransGo
2621 Merced Avenue El Monte, CA 91733 USA
Calibration | Innovation |Performance
https://transgo.com/our-products/
Hey Robert. There are two brake switches.. One that is normally open that runs the lights. The other is normally closed and will keep the torque converter from locking especially off the gas in GEN3. I would assume GEN4 also. Common for hotrod swap guys to forget to hook this up and the moment you come to near 0% throttle the TCC will unlock
460632d1405619737-tcc-brake-switch-tcc-brake-switch.gif
Tuner at PCMofnc.com
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Interesting when I looked it up the other day it I looked up the colored wiring schematic (should have known better) and it shows the switch as being normally open.
Color.png
But using the same VIN from the tune looking up the black and white diagram just like the diagram you showed for the 4L60E it nows shows it as being normally closed on the 4L80E as well.
OEM.png
Normally closed is most likely the correct one since the black and white is factory wiring diagram. Definitely need to take a second and look on the scanner data to see if it is workign as it should. Maybe I missed that this was already done and the signal is wrong which would explain why the OP is looking for the fuse location, my bad if that's the case. Here's a screenshot where I put a red box around the brake fuse in the instrument panel fuse block.
Fuse.png
Robert Moreau
Technical Sales and Marketing Support Specialist
TransGo
2621 Merced Avenue El Monte, CA 91733 USA
Calibration | Innovation |Performance
https://transgo.com/our-products/
Ok thanks Robert I actually have one of your hd2 shift kits in the trans and I really like it. i will try the fuse and see what happens. By what I understand that will fix what I want. Thanks for your help and I will see what happens!
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