TCC Experiment

[dkjones96]

It's installed and I gotta say that I like the new toy.

A couple of things I've noticed, the red indicator is pretty worthless, the transmission apparently has a hydraulic lock-out to prevent the transmission from locking the torque converter when the transmission is in first gear meaning I could just leave the switch in the 'on' position and forget about it. Well, almost. The transmission computer is relying on the tc slipping to keep revs up when it does a part-throttle shift so you can take off fine but if you don't let the engine rev up you find yourself in second gear at 750rpm(it locks the instant the transmission is out of first) and a car that's shuddering pretty badly. This also happens if the transmission is in overdrive and the rpms fall under 1300 rpm(~30mph) where it normally would just keep in overdrive and slip the tc.

Shifts through gears aren't that bad, a little firmer but nothing to call home about. However, cruising at 45 and flooring it so the transmission downshifts to second gear feels just plain nasty. I'm going to try and increase transmission line pressure to firm up the shifts a bit but I shouldn't be doing that anyways.

On the freeway, the downshift out of overdrive for a hill or something feels fine and I don't see a reason to really worry about the transmission taking a beating. In town, I can now keep the tc locked as low as 30(in overdrive or 20 in 3rd) and when I'm coasting to a light in a 45 zone I can manually unlock it which is allowing me a longer coast down on speed without going into neutral. On the flip side, I'm able to lock the converter and accelerate(and cruise if i watch my gears) with it locked in town as low as ~18mph as opposed to the 36mph the computer is programmed with.

[Jay2TheRescue]

Sounds great. Would it be possible for you to sketch out a quick schematic? I was thinking about installing a switch to manually lock the TC on the Beast.

-Jay

[theholycow]

Sounds nice. If you could come up with some better control of gear choice (or at least lock it in gear when the TC is locked) it would be even better. I'd like that, myself...

[dkjones96]

Originally Posted by theholycow

Sounds nice. If you could come up with some better control of gear choice (or at least lock it in gear when the TC is locked) it would be even better. I'd like that, myself...

That's actually easier to do then you'd think, on an electronically controlled transmission anyways. To control gear the transmission computer only deals with two solenoids in two positions, for example in my car:

Gear.......Solenoid 1......Solenoid 2
1.............ON................OFF
2.............ON................ON
3.............OFF...............ON
4.............OFF...............OFF

All you need is something that can output 12v to those based on what you have selected manually(gear). Could launch in overdrive if you wanted... but who'd want to.

I'll get a schematic of what I built up tomorrow.

[theholycow]

If it turns out to be that simple, I have a new project to do...

[theholycow]

Er...I just remembered the specific reason why you should unlock during shifts: The clutches/bands in your transmission. You may be thinking that it just jams it into gear and the engine just absorbs the shock, but actually the transmission absorbs it using its stuff which is more sensitive than the TCC.

You might want to rig up a footswitch (look at the ones used for trolling motors on bass boats) to unlock and press it when you expect a shift.

[dkjones96]

Anyone know of a program I can use to build a simple schematic? This thing is driving me crazy and even Visio sucks.