Freezing the Slushbox. Torque Converter on-demand lockup switch.

[RobertISaar]

i've done it through reprogramming... rather than waiting for 45MPH for the TCC to lockup, i'm now in the 30MPH range(with lockup in 3rd and 4th gear, rather than just 4th), i like the feel of it, engine feels much more connected to the wheels, rather than spinning/slipping the torque converter up to the ~2100RPM stall point.

some people don't like the feel of it though.

i need to see if i can patch in the ability to use lockup in 2nd gear without lowering the temperature threshold to operate the trans in hot mode all of the time.

[japcarmaniac]

Originally Posted by RH77

Well, sort of. My mod is simply a switch to energize the 2 lockup solenoids with 12VDC, which allows TC lockup and signals the TCU to just up-shift at the lift of the go pedal (that is, when conditions permit -- throttle position dictates hydraulic pressure to engage varying degrees of lockup and is dependent upon the stock circuit to monitor coolant temps on cold starts to restrict short-shifting to higher gears). Every transmission is different, so the trick is to experiment with engine load and type of lockup method.

Despite the effort, that near-direct link between engine and road surface is valuable for FE. Once locked, it stays locked until switched-off... or when slowing down to a near-stall point, partial-lock is mandated and lightly lugs before downshifts (and stays lightly locked while stopped). This still keeps the engine running, but it's under load and forces lower RPM if you forget to disconnect. It's an enjoyable challenge to treat it like a manual and place automatic transmission control back in the hands of the driver.

Once everything is warmed-up, up-shifting is as easy as lifting the throttle (downshifts are accomplished through the shift stalk or harshly through high throttle input). Sometimes it's a bit too aggressive and needs some intervention (engine lugging, direct lock on decel = more compression braking, and finesse with the throttle to avoid excessively harsh shifting, either up or down, is needed). An investment in synthetic trans fluid has helped with any undue stress and/or temps if lockup is delayed or negated since a "stock mode" hasn't been wired for other drivers.

Basically, transmission selector positions 1, 2, D3, and D4 will hold or downshift manually as selected, and upshifts are aggressive enough for me to call it "manual". YMMV.

Have fun...

RH77

I had a thought today. I've been researching other things I'm planning to do and I seems that a lot of honda guys use chipped auto ecus for tuning but the downside is they lose all TC control so no TC lockup whatsoever. What if I replaced my ecu with its full manual equivilant. So no tcu whatsoever. Then from there control my TC via the solenoid at will and shift manualy using the shifter with no influence from a computer trying to fight back all the time. It would almost be completely manual all the time minus clutch control. I've also replaced my ugly shifter with an aluminium knob and stock gaiter for a more ergonomic feel so no button pushing just up and down shifting.

[Christ]

Originally Posted by RobertISaar

i've done it through reprogramming... rather than waiting for 45MPH for the TCC to lockup, i'm now in the 30MPH range(with lockup in 3rd and 4th gear, rather than just 4th), i like the feel of it, engine feels much more connected to the wheels, rather than spinning/slipping the torque converter up to the ~2100RPM stall point.

some people don't like the feel of it though.

i need to see if i can patch in the ability to use lockup in 2nd gear without lowering the temperature threshold to operate the trans in hot mode all of the time.

Duno how well it would work, but you might be able to keep the transmission warm by putting a second pan on... use the opportunity to change the filter and fluid, and instead of using the original trans pan bolts, use allthread, bolt on the first one, then put the second one on loosely and fill the void with expanding foam. The pan is where much of the heat of the transmission is lost during lockup [when the cooler path is closed].

[RobertISaar]

i see no reason to force my trans to run hotter? the 4T60 series of transmissions don't take kindly to more heat than necessary. in the winter, 150-160*F trans temps are what i see after a long driving period. in the summer, it eventually creeps up to engine coolant temps(so 195-205ish).

if i wanted to force hot mode all of the time, i could simply lower the temp thresholds before it is enabled.... that is the only way in the factory program for the TCC to lock in 2nd gear. patching in some functionality to allow this isn't difficult, but there is something along the lines of 30 bytes free in the calibration before needing to remove stuff.... not enough room to fit in non-hot mode 2nd gear TCC apply/release tables. enough to do a blanket "whenever in 2nd gear, lock TCC" patch, but nothing more sophisticated than that.

[Christ]

I dont' know much about the TCM setup in those... the extent of my ECM/TCM knowledge deals with OBD0/1 Hondas and building/mapping custom ECM units.

[orange4boy]

Have had this set up on my Toyota Previa for years now.

It will stall if you come to a stop with the switch on, TCC locked up, but drives "normally" otherwise. It will shift too early if you accelerate too slowly causing some lugging but then if you are accelerating too slowly you are not doing you FE any good. Manual shifting is done with the shift lever but it is not required. My vehicle comes with an overdrive button which is the final gear selection. That's the one I use the most to keep revs at a good level when cruising at lower speeds.

Makes the vehicle fun again. Feels like a standard transmission with auto shift.

One wire job in my vehicle.

[japcarmaniac]

Originally Posted by orange4boy

Have had this set up on my Toyota Previa for years now.

It will stall if you come to a stop with the switch on, TCC locked up, but drives "normally" otherwise. It will shift too early if you accelerate too slowly causing some lugging but then if you are accelerating too slowly you are not doing you FE any good. Manual shifting is done with the shift lever but it is not required. My vehicle comes with an overdrive button which is the final gear selection. That's the one I use the most to keep revs at a good level when cruising at lower speeds.

Makes the vehicle fun again. Feels like a standard transmission with auto shift.

One wire job in my vehicle.

so you have not completely removed the tcu?

[orange4boy]

No. Found the solenoid wire at the main ECU, cut it and wired in a switch on my shifter. Took 10 minutes.

[t vago]

Originally Posted by ksa8907

I gave up on the idea. Seemed a bit risky to play with the tcu directly, plus the advantage would be no slipping at high loads but that would probably tear up the clutch since its small. Going to get a new gauge cluster this week so I can use autostick instead.

Hm... My transmission solenoids (42RLE) also require PWM to operate. I wonder if I can convince an Arduino Uno to become a TCM.

[orange4boy]

Hm... My transmission solenoids (42RLE) also require PWM to operate. I wonder if I can convince an Arduino Uno to become a TCM.

Solenoids don't require PWM to operate. They require the PWM signal to modulate pressure. PWM is simply a way to make the solenoid see lower voltage without using a resitor. This is not needed of you don't want the clutch to slip, which you don't. If the clutch is not slippping, it will last much longer, if not beyond the life of your car. It is not small. The TCC is quite large for what it does.

The simplest way to do this is to bypass the TCU signal to the solenoid with full voltage or ground, depending on your particular system. To stop codes, you can put a resistor in line with the original TCU wires to make it "see" a solenoid. The resistor is a false load.

Much easier than programming an arduino to be a TCU!