Wouldn't you think that if the torque converter is defective you would have the supplier pay for and/or fix the torque converter? If the torque converter supplier paid for the ABS upgrade then fine. It looks like it went from a tremendous out lay to a tremedious profit.
Seriously if anybody knows the reasoning I very much would like to hear it.
I'm not sure why we're blaming AM General for this issue. AM General did not design the transmission, and I doubt they had much if any input into the manufacturing of said transmission. It was selected based on specific mission criteria; Allison supplied these transmissions from existing production. The MT654 is not unique to the M939 series trucks, or to military applications. It's found in a wide range of on and off-road trucks and buses.
My understanding is that this behaviour is a result of an intended design feature of this (and several others) model Allison transmission. Additionally, it has been my experience that these transmissions perform the same way in every application in which they are found. They lock up early, at the top of second gear just before going into third, and don't unlock untill coming out of the bottom of second into first. If I understand the reasoning and operation correctly, it is to provide positive engine/transmission braking, and also to reduce slippage under acceleration, which also reduces heat generation, increasing transmission durability and longevity. Someone who has a better understanding will correct me if I'm mistaken on any of this.
Seems like if it really was a "design flaw" as some have indicated, the correct solution would have been having Allison address the issue, and let them "break" the functionality, since it's their transmission, and their design feature, and was provided to AM General like that in the first place. How simple (or complex) is it to change the lockup from second gear to fifth gear? Swap out the torque converter and move on, right? Interestingly, that's not what they did, though it might have been cheaper than installing ABS.
The ABS modification provided safer braking controls, which were needed anyway, and maintained the existing transmission functionality. Win-win, I think. And as somebody else mentioned, a bargain at the pricetag given.