mckellyb

I know this goes against what the LS 460, especially a LWB one, is at the core...a high-end luxury vehicle, built to effortlessly, and in supreme comfort, munch major miles...however, I'd love to 'tighten up' the transmission's shifting a decent amount. I've never been a fan of transmissions which 'slur' their shifts, but even on 'PWR', and a week after changing to synthetic trans oil + a new filter, while it feels a little quicker/firmer, give me what some would consider harsh shifts, and I'll be happy.

I had the transmission computer in a '05 Cadillac STS tweaked to shift as quickly as a C4 Corvette. It'd hold gears and bounce off the limiter if I wanted, and unless at low speed, it'd shift when I told it to, if in 'manual' mode. I really wanted it to, if I put it in 5th at a stop, to actually be in 5th and to stay there until I told it, otherwise. This is just an example, not actually useful.

This Spring, I plan to modify the valve body/converter locking of the Torqueflite 46RE in our '98 Jeep 5.9L to be, if I want, effectively a manual without a clutch pedal. Getting around the converter lock is easy on that beast, just remember to unlock it before coming to a stop! I know a guy who may be able to build a switch for it which works under certain conditions (at least 2nd gear, not in low range, OD switch not 'off').

However, the IS-F's computer does exactly what I want. It's aggressive, even locking the converter in 2nd while in "sport"...AND SHIFTING LOCKED! From. The. Factory.

Yes. This is what I want as my manual selection. 0.1 second shifts and shifting while locked up.

The IS-F put out about the same torque 460 (371 vs. 365), so we're safe, there. But the electronics...I wonder if they play well. The computers, based on fleabay images, have a different connector layout, so it's not 100% plug-n-play...probably. But it's unclear what goes where and if it'll even work. Plus, IS-F transmission computers aren't inexpensive for a what is, for now, a knowledge experiment.

I happen to have a spare, non-sport, suspension computer on the dining room table for reference on plug size/shape. I may post over on the IS-F board, too...they may know, and are more likely to modify stuff like this (and here I am, thanks for having me).

Thanks!!!
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lobuxracer

iTrader: (2)

Sounds like an interesting project, but would require a whole lot more homework than just connectors and pinout. While it is true both have the AA80E transmission, the TCU and ECM do a whole lot of talking, and if you swap the TCU from the IS F into the 460 the TCU and ECM may not speak the same language. Or they might. This isn't something this forum is likely to know since we already have this functionality from the factory.

mckellyb

Thank you for reinforcing the danger of this particular rabbit hole, because I'm on the edge of it, peering in, and it appears bottomless...potentially.

Again, thank you very, very much. Seriously.

lobuxracer

iTrader: (2)

The IS F TCU has 2 connectors and 39 active connections to other parts of the control systems. The ECM and TCU communicate through the CAN bus, so there is some hope at least these will be able to communicate, but it is only hope.

The LS 460 TCU has 4 connectors and 40 active connections, but the extra connection is a ground required for the 460 TCU. All the signal connections are the same, but all the wire colors are not.

The pin types in the main connector for each are mix and match. The big pins are the same, so you could transfer them directly to the new connector shell. The small pins are not the same, so transferring them directly is questionable.

The other piece of this is initializing the TCU requires Techstream, and who knows how that might go because Techstream doesn't support non-standard configurations like this. It might work just fine. It might make you regret all the hours it took to move the wires and get the connectors sorted out.

If I were doing this, I'd make a subharness by cutting the existing harness connections off the IS F harness and building an interface to the LS connectors. That way, you could do all the hard work without disabling the car, then plug in the parts you want to test, attempt to configure and go from there. Still a pretty daunting task if you ask me, but it would be interesting for sure.

mckellyb

Well, at least I could make adapters on the bench, then plug-n-play. I thought I found a picture of the IS F's computer which showed it had a pair of connectors on opposite sides, but I've read some of what you've posted over time, and I trust you more than my eyes on this.

I'm going to back away, slowly, not make any sudden moves, and attempt to forget I thought about this...

...but I really want...no, no, no...BUT...no I don't... <smacks self a few times>

edit: Thank you, Google images for confirming! My Google-fu was off, yesterday, it seems.