Stock Torque Converter and AWD launch

[Josh P]

I'm wondering if a switch could be used to lock the converter in 2nd? An arduino could be programmed to look at the gear, speed, etc to lock it up

 

[MuscleJunkie]

I'm wondering if a switch could be used to lock the converter in 2nd? An arduino could be programmed to look at the gear, speed, etc to lock it up

What would be the benefit of this..... what would that do?

 

[Turdle]

In normal use the converter doesn't lock up, but WOT is different. High performance vehicles typically do lock up in the upper gears. I don't know if these Explorer 4R70W's are programmed to lock up in 2nd or 3rd gear, I doubt it. 4th gear is no issue since that's the OD band and cannot handle WOT ever.

So for racing it only has three gears, you have to reach 1320 feet before you run out of 3rd gear. Jim has stock 3.73 gears so he might be getting close now to its limit.

Lockup in 3rd and overdrive only, but not sure about wot lockup.
In stock tune you'd be past the speed limiter at that point
Any gear lockup can be achieved with a switch, but that would be dangerous if in case a shift was commanded and you forgot to switch it off

 

[MuscleJunkie]

So lockup prevent transmission from shifting - similar to when you manually put the lever into one of the other gears (other than D) and it will not shift to the next gear???

 

[CDW6212R]

If you keep the OD switched off, it should stay in 3rd and gain rpm, to whatever rpm you feel comfortable with. If you let it go into 4th, by letting off the gas briefly, it'll go into 4th and try to keep pulling. Don't do that, you will be testing the limits of the OD band, and they don't last long at high throttle.

I pushed my 91 Lincoln AOD in 4th twice I think for a few seconds each time(eased on the gas after letting off a moment), and didn't kill the OD band(which is thinner in the AOD). The 4R will probably survive long enough to make you think it can handle it, and then some unknown time later, it'll be slipping. I'd say you have been lucky so far, and don't push it any more. The 4th gear will also be likely to start slipping if you tow a heavy load on the highway, and drive it for a long time in 4th.

 

[Josh P]

What would be the benefit of this..... what would that do?

a torque converter slips some, add boost and it slips some more. So some of that new found power is heating the transmission fluid up instead of making the car move faster. Some people will lock the converter in 3rd going down the track and have reported faster times.

 

[Turdle]

Turning od off, allows and commands 3rd gear lockup of tc.
Used for towing and climbing steep mountain roads, this will keep trans temperature lower. When the torque converter is locked, the transmission cools rapidly. No slip no heat