No does not see it.

see / read http://www.cumminsforum.com/forum/3...com/forum/3rd-gen-powertrain/107415-3rd-gen-mystery-switch-diy-works-great.html

 

As long as you run your circuit through a 33 ohm resistor, the PCM will not "see" the ground on the circuit.

I would avoid allowing it to shift between the first 3 gears, upshift or downshift, with the converter locked. A 3-4 upshift and/or 4-3 downshift with the converter locked is just fine. Your valve body may not allow a 4-3 downshift with the converter lock, though, depending upon how it's setup.

 

Yes, it will prevent a downshift. It will also stack shift it right into OD with light throttle.

Yes, with stock parts locked to locked shifts are very hard on the transmission. Stock programming never allowed that for a reason.

 

Yes, there are a couple of hydraulic circuits that come into play affecting gear changes (assuming a stock valve body). I thought he was asking about the PCM "seeing" the ground and preventing gear changes electronically.

You can shift 3-4 and 4-3 with the converter locked without any problem whatsoever.

 

The 4-3 downshift is not really an issue but the 3-4 is REALLY hard on parts, especially with a tuned engine. Way too much TQ rise on the big rpm jump and not place to slip. More rpm the better but still not a recommended for stock parts.

 

Based on what experience? And what parts would you recommend upgrading to make it "safe"?

BTW, I've been running them this way for a couple of decades. But, then again, I run triple disc converters on stock input shafts every day as well. I must be the exception to a lot of rules...

 

There are no parts to make a locked to locked shift "safe" in an LD transmission, all that can be done is minimize the TQ hit. Even HD transmissions do not try to do that, always an amount of TC slip built into the logic on shift points.

Unless you have been reprogramming every truck and modifying every VB to allow locked to shifts it isn't happening. If it did that you would see a LOT more failures. Even with billet shafts locked to locked shifts break stuff with enough traction and enough TQ, chiefly cases. The only reason you get away with running a triple disk with a stock input is by slipping the TC on shift points, that is not a mystery it is simple physics.

 

Many customers with lockup switches, and several of my own trucks with them, too. Locked 3-4 upshifts and 4-3 downshifts all day long; daily driving, towing, whatever. Zero failures...

 

Deleted because it serves no purpose

 

Deleted by Dynamic...

 

Thanks for the input. What about running the ats copilot? Will it momentarily unlock the tc during shifts? I'm planning on getting an exhaust brake. I frequently gross 25,000#, sometimes up to 32,000. Trans was rebuilt by prev owner in Idaho ' by a guy who builds trans for the ranchers '. It has some billet parts but don't know exactly what. Also has 80 hp injectors and edge controller.

 

Dont purchase even a simple washer from ATS. Just dont do it. Everything they make is complete garbage. The firepunk anteater is the preferred controller.

With that kind of weight, I personally would be hesitant to run a lockup switch on anything but a FMVB. You simply cant get the control you want with a computer. Other than maybe stock programming which isnt adjustable and short shifts like its going out of style.

But it's like I've seen so many times before.. People running stock output shafts doing 15psi 4wd launches many many times and it takes a long time for the shaft to let go. Some people get away with murder, me, I cant get away with anything. I would break a fat input doing a 5psi launch at stock power with how things usually go for me.

Like I said, with that weight and upgrades, I would be hesitant to run a switch, but if you are smart about it, it could work very well.

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