4EAT: do anyone of them come with a fully locking torque converter?

[wagonist]

As per the title, and I mean that the torque converter locks up in every gear rather than just 4th.

 

So the engine will rev up more like a manual instead of slipping as you accelerate & then the gearbox plays catch up.

 

And if so, can the later torque converters fit into an 89 Loyale type 4EAT?

[skishop69]

Lockup in gears other than 4th was not available until OBD2. That being said, I'd say most likely no, the later converters won't fit, but I'm not 100% sure on that and if they did, there'd be nothing to gain.

[golucky66]

I honestly don't know a huge amount about how automatic transmissions work (in depth at least). But isn't the lock up just fluid pressure being applied to the torque converter. And therefore is a solenoid that controls that lock up? Couldn't you in theory run a switch to manually lock up the torque converter? 

Obviously that would never be practical, if even possible. But just curious. 

[wagonist]

Why do you say there'd be nothing to gain? If not, why did all the manufacturers do it?

 

I reckon there'd be a gain in stop/start traffic & in hilly terrain. Not all of us live in countries where fuel is almost cheaper than water

Whether the cost of doing the change is worth it vs the saved fuel is another question entirely...

[Numbchux]

I agree that it's probably in the programming of the TCM, not the converter itself.

 

 

First gen Legacy TCMs have been hacked, reprogammed, and retrofitting into EA82 cars....so it's definitely all doable.

[skishop69]

Ok, you'd gain some fuel economy. Here's the thing with lock up: When they started locking the TC in gears other than 4th, it was partial lockup. Only under very light throttle at cruise in 3rd & 4th (sometimes 2nd depending on the manufacturer) did it lock fully. The TCC solenoid is pulse width modulated (PWM) meaning it has a duty cycle from 0-100%.  The higher the duty cycle, the more apply there was with the TCC. They did this so that partial apply would allow the engine to operate in the most efficient part of the torque curve in relation to the gear it was in. The TCM's used in the first gen Legacy hack would have been OBD1 and not capable of partial lockup until OBD2 came about. With OBD2, the TCM would be looking for information and communication coming from the ECU and without that info, it wouldn't function correctly. In addition, OBD2 needs signals from an input speed sensor (ISS) and trans fluid pressure (TFP) sensor in order to control shift pressure, shift points and TCC slip. The OBD1 trannys didn't have these sensors so I don't see how an OBD2 TCM could work even if it were hacked unless it were reprogrammed with a base control map that that didn't require any input from sensors. If that's how it was done, then I doubt that the lockup is going to be operating at the peak efficiency since it has no way of knowing engine load or slip speed so fuel savings would be pretty small if at all.