Ive read about the lockup switch and this is not a question about how to do it. what i really wanna know is is there a way to modify the valve body for the truck to shift into second lockup on its own with no switch. so that way when it goes to shift into 3rd the converter will unlock so it doesn't shift locked? i don't wanna worry about switches or breaking anything. I'm having a triple disk and a billet input shoved in there and my tranny guy is tweaking the valve body and i want this thing to eat some rich kid trucks. thanks guys.

 

IIRC lock up only happens via an electrical signal. The only thing I think you might get out of tweaking the VB is firmer shifts. You will need a switch and have to keep flipping it on and off for each shift.

 

If I do a manual switch can I switch it on in second. And before it shifts into 3rd flip switch to unlock so it doesn't lock shift? Or does it not work like that. I o lay really want to do this if there is low to no risk to messing my truck up. Thanks

 

Yeah you can do that. Just make sure you don't shift while locked up. Otherwise you will have more problems.

 

You're gonna have to spend money like a rich kid to beat "rich kid trucks" in a VP44 Cummins.
You can shift it locked. I've got a triple disc and billet input, with a tuner and injectors, and I do it all the time.
When you hit the switch, it will upshift a lot earlier. If you have your foot in it, it will lock in 2nd when it's in Drive (until it uoshifts to 3rd) but it won't lock when manually put in 2nd unless you block a certain passage in the valve body. You can look up the mod for that. I'm gonna do it. It needs it going up steep hills with lots of weight behind it so the tranny doesn't overheat.

The lock button makes a HUGE improvement... I've begun calling mine the "quit screwing around" button. Even with a tight low-stall converter, when you get on it it seems to just make noise and rev uselessly while going nowhere, particularly with some weight on it. When you hit the button, it just GOES.
I have also learned that you don't use it in the rain... then the switch is called the "truck go sideways" button.

 

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Well I got tranny built and a triple and billet shafts weren't in budget. I had a dual disk shoved in and everything else has been upgraded and replaced. I'm going to sell my edge and upgrade to a quad and shoot water meth on top of my other goodies. Would a lockup switch still be smart or not. I can't afford anything to break.

 

I'd still do a lockup switch but I'd just be a lot more careful how I used it.
Often I just hit it after the converter locks on it's own so that it doesn't (annoyingly) lock and unlock every time I take my foot off the gas.

 

If I lock in second how do I time it to know when to unlock it before it hits 3rd?

 

There's really no way to reliably do that, short of modifying the valve body so you can manually hold it in 2nd and decide for yourself when it's going to shift.
On a stock input shaft and a cranked-up motor you're playing with fire here.
If I had your setup I'd install the switch for the reason I meantiined about stopping it from clubbing in and out of lockup every time I let off the gas, but I think I'd resist using it to haul a$$. There's too many horror stories about broken input shafts.
I feel your pain, I couldn't afford the billet shaft either... I just decided I couldn't afford busting one even more!