So right now when I hit right at 40 my TC lockup engages and makes it hard for my truck to accelerate from there. Is there a way to change it to where lockup doesn't engage until closer to 50 or 55? Thanks!

 

If you're on stock size tires and stock ratio diffs (and the transmission's not sending the wrong signals to the PCM), it's probably overdrive rather than TCC lockup. Poke the button to make the OD Off light illuminate and see how that goes for you.

 

Yeah, The OD engages at approximately 45 depending on conditions. You can get the pcm reprogrammed to raise the engagement. Not sure if there is shift kit that will do it?

 

Overdrive is electronically switched and the controls aren't in the transmission, so it'd be tricky to get it done from there.

 

My sonnax raised it to 50. Electronically controlled based on readings it gets from sensors, readings a shift kit will change

 

Fiddling line pressure (or line pressure signals) probably moved all of your shift points though, didn't it? That part of my brain that thinks it understands things expects that, but the larger part of my brain that knows the world doesn't often make sense is telling me that I should just shut up now...

Disregarding in-town driving where overdrive doesn't happen for me because I've got the habit of poking the button at startup, mine was at 50 MPH indicated (speedo) under light acceleration on the factory unit and stayed at 50 on the Mega Viper. When I threw away the larger tires and went back to stock, it stayed at 50 indicated even though engine load was proportionally lower. What made the big difference for me was the tuner, which when set to go-fast makes the PCM more aggressive in switching that flip. It's now almost perfect for most of my highway driving, but I still switch off manually where it'd otherwise do too much shifting. I'd call it the ultimate reality if the thing could detect injector shutdown and respond by dropping into direct drive and enabling TCC lock, but it's not killing me to manually push the button on downgrades to get that functionality. It's not like anyone ever rolled a really good mountain truck off of an assembly line...

 

No you're exactly right. All 4 shifts are higher especially under WOT. The canned tune i have raised them slightly but most is due to the sonnax. At WOT 2-3 shift occurs at 5100rpm and 80mph. 1-2 shift i have to let off slightly at 5k otherwise it'll go past 6k without shifting lol.

I also push it every time i get in. I don't want it o/d to engage unless I'm on the interstate or highway between all the small towns here. I've noticed significantly lower temps and the trans just acts nicer all around, especially in the summer

 

 

Yeah that was my bad, it is OD I was talking about

It goes 1-2 2-3 then TC lockup then OD right after


It's annoying because it shifts into OD at a little under 40 mph and it'll be running about 1100 rpms

 

And I forgot to say, I'm on 4.10s and 33s