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

After much frustration with the Previa's slushbox and the inability to P+G properly I have decided to try to bypass the ECT and put in a switch to get lockup in all gears. I live on an island with a low speed limit and steep hills so the TC almost never locks up. Im not sure how much this will help my FE but I'm determined to try it because I suspect it will. The manual transmission gives the Previa 16 mpg over the 15 the auto gets in city driving. That's 6% better and I bet it's more in hilly conditions. So if those losses are mostly the TC losses this should help. Trying to find a stickshift for the Previa is like trying to find something really hard to find: Hard. To find.

I looked into this and asked Christ some nagging questions and have decided to give it a try.

Most of the reasons for the lack of TC lockup at low speeds are about "driveability" and power. It reduces shift shock and at low engine temperatures, increases driveability. Who needs driveability? I have been told that many new Auto transmissions lock up the TC in all gears for better FE.

One question I have is about shift shock: would this damage the transmission or drivetrain? I drive pretty light on the throttle so I'm hoping this would mitigate the shock but I guess I will find out how strong the shock is if I get the bypass to work.

If so I may look at a way to apply lockup unless the transmission is shifting. this may require a skillset beyond my own if it means modifying the ECT.

I plan to set this up so when the brakes are depressed the lock disengages which is one of the ways it's controlled now.

Thoughts? Suggestions? Warnings? Colour commentary?

I'd be wary of using the torque converter lock under high torque situations. Many cars are made with as little a TCC lock up clutch as they could and they just can't handle high torque and will fail. Many mustang owners have done the TCC switch and killed thier converter this way, of course they are trying to use it for better 1/4 times etc...

Rick has done this before on his integra, I think. So hopefully he can chime in with some thoughts on the experience.

Do you know if they fail because they burn out from slippage or is it a structural failure?

If it can't take the torque of the hills then I will have to content myself with low speed cruise.

I just found this great post at Toyota nation about how to bypass the ECT and set up a manual shift switch with on demand TC lock up.

The Free Mod Series: Part VIII Electronic Transmission Controller - Toyota Forums :: Toyota Nation

You can set up a 6 position rotary switch that give you the ability to change gears at will which is great for FE because I will be able to shift up sooner.
It's just at the limit of my skill level although I might start with the TC lock up first for simplicity.

There might be a problem with the lockup switch first approach.

If you don't control WHEN the transmission shifts (i.e. with the rotary switch) then it seems probable that you have some gear changes under power without any tc slippage (oops, didn't anticipate that downshift in time). I don't know how big a concern that is though, might just be an occasional hard shift.

I'll find out how harsh the shifting is then decide what to do. From the sounds of it, the shifting isn't that hard. Off road guys do this all the time. You can even buy kits to do on demand TC lock up.

If it's too harsh what I will need is a rotary switch that requires me to unlock then shift, like the push button lockout on an auto tranny. Hmmm gets me thinking.

Lock up the TC and you cut the flow of ATF to the cooler. Heat builds up and expensive and often spectacular (a trail of parts and fluid scattered down the road) transmission failures follow.

Face it: The automatic was never intended for hypermiling. The manual transmission is far superior.

I like the idea...the TC in my Mom's Mazda is far, far too skittish...

Lock up? Affirmative!

Time to wire? Ten minutes, sir!

Just got it working this morning. This is a temporary set up with no "ghost" resisitor to fool the ECT. I just cut the TC lockup wire, found a 12V+ to power it and put a momentary micro switch in to complete the circuit.

First impressions:

There was a rumbling sound the first time I switched it on. I was in 3rd doing about 30 mph. At first I thought this was the TCC slipping but it turns out it was the engine rumbling from being at too low an rpm for the gear. When I tried it again I downshifted to 2nd and it was great. Solid and smooth. I miss that direct connection you get with a standard tranny, now I has it.

Now I need a tach to learn the shift points because I can't hear the engine.

This will work better with the full control for sure because the gear chosen by the ect is too high for the TC to be locked. I may be able to make it work better by adjusting the downshift cable. Will have to try that out later.

For now it will stay a momentary switch.

Is this true on all automatics? Some of the newer ones must have fixed that issue because they now lock up the majority of the time. (obviously not mine)

I would imagine that since most of the heat generated by the transmission is generated by the inefficiency of the unlocked TC that over heating from a locked TC is a non issue. But since TCs normally lock at highway speeds, I guess all that wind does the trick, cooling it from the outside. Doesn't this essentially turn the auto into a manual (which cools passively) in terms of heat generation? Where is all this heat being generated?

Would it be prudent to install a temp gauge in the tranny to make sure? Most of my trips are too short to cause that much heating.

I totally agree. I hate them. But since I'm stuck with slushbox, a ten minute mod to reduce the losses sure beats installing a manual transmission in my Previa IF I could even find one.

i dont know if all do it or not, but youre right on the money with your guess why. most of the heat generated is from the converter slipping, and why cooler flow isnt required during lockup

2nd run complete. Working great.:D

Observations:
TC lock does not engage in first gear. The safety there is still working even with the bypass switch. Not really a problem since I spend very little time in first. My driveway will have to be slushed. Fitting, really.:rolleyes:

Second gear is pretty long so I have to start unlocked but I can get locked at about 40Kph / 25mph. A little below that on the flat and it needs to be going about 45kph / 30mph to do the hills here without bogging. (I'm not sure of the rpm shift points yet.):confused:

Shifting into 3rd is not harsh at all under the conditions I tried it (slight up grade). There is a little "mount bounce" after the shift but it's very mild.

I believe OD is really just fourth gear so that has to be disengaged or it will shift into OD too soon after 3rd. The tree is really a pain for this type of driving so I'm dreaming of finding a suitable shift lever to replace the original.:cool:

OK, that's the last smiley.:o

http://ecomodder.com/forum/member-or...background.jpg

You can see the lockup switch elegantly taped to the tree, my digital vac gauge (thanks Vtec-e) and my temporary, tacky low tech tach.
I like the washer fluid button in this pic. It's all "OH...OH...pick me...pick meeeee."

http://ecomodder.com/forum/member-or...lock-brown.jpg

I need to figure out which of these wires is for solenoid one and two. I already know the green/yellow is #3
Anyone? ...... Anyone? ..... Bueller? ..... Bueller? .... Bueller?

http://ecomodder.com/forum/member-or...river-seat.jpg

This just shows how easy it is to find on the Egg. (Small mercy) The ECU is the ONLY thing engine-wise that's easy yo get to.

I'm not sure about this... I try to get locked up as quickly as possible, and accelerate under as much load as I can put on it without unlocking... I've never had a problem w/ my transmission.

Why would locking the torque converter into 1:1 operation cut ATF flow when you're still turning the pump?

I'd think that if that was true, many people would have highway transaxle/transmission failures, no?

#1 - BN-W pin#15@ecm conn.C pin#13@conn. IH1
#2 - BN-Y pin#14@ecm conn.C pin#12@conn. IH1
#3 - G-Y pin#1@ecm conn.C pin#11@conn. IH1 <---lockup

Just about any floor shifter that has a cable attachment can be made to work for you, as long as you have the guts to put a hole in your floor,and you can actually reach it once you're done.

Thank you 2000mc. You rawk!

This is true in some transmissions although I haven't confirmed this in my particular one. Whether this would cause a transmission failure due to overheating, I also have not confirmed, but it seems illogical.

The following is not typical. You should check this out on your own transmission like I did but I highly doubt overheating from lock-up is an issue.

http://www.kaps.cz/data/news/paragra...otos/687_1.jpg

http://www.kaps.cz/data/news/paragra...otos/688_1.jpg

i didnt see what sol. is on and off to get you each gear, but i suppose you could hook up a test light and drive it to figure that out. tricky part might be that one of the shifts require switching both sol. at the same time

There is a chart in the Toyota transmission course that shows the pattern of solenoids to gear selection. I just needed the #s:thumbup:

I guess we can put the overheating issue to rest:

From a very trusted source in the UK:

So there you have it. Not an issue on the Previa. I like to know these things for sure.

This is working so well. I can finally accelerate at low rpm with high load.

(In the voice of Bill Bailey) "I can now travel to the magic BSFC island of efficiency."

http://www.youtube.com/watch?v=O3F2e-x_EU8

Do I understand correctly that the momentary application of 12v initiates lock-up and it stays locked or do you have to hold the momentary switch? In my case, since the circuit gets grounded to lock up I will need to provide voltage to the computer end of the circuit to fool it.

Are you sure you don't have that backwards?

In the Previa, the TC lock is engaged as long as 12V is applied to the signal wire that goes to the solenoid. I will have to hold the switch to keep it engaged. I will later install a parallel on off switch so I can leave it on on the highway with out having to hold the momentary. I need the momentary for island driving because of the speed changes on my route and because the gearing is too low for the shift from first to second so I have to engage the lock part way through second gear.

Can you set up a circuit with a momentary switch that will turn it on/off based on pushes?

First push - on indefinitely
Second push - off indefinitely
Brake application - off if currently on, nothing if nothing.

I'd think one of the nice programmer people here could program a controller for you, if you ask nicely. ;)

I just wired up another, better switch. It's two, two, two switches in one. A toggle and a momentary, side by side. I wired them up parallel and it works great. My brain on the other hand, not so much. It's like learning to drive all over again, I get the wrong gear about 20% percent of the time. But once I get into the habit, it should be more like 1%

I also installed a tach which is pretty mandatory because I can't hear the engine any more, it's revving so much lower.

I love, love , love the TC lock. And did I mention that I love the TC lock? I always disliked the auto but now I have a semi auto. Close enough.

Quieter, smoother, more betterer. I'm one happy ecomodder:D

That would be the icing on the cake but I'm happy to drive it like this for a while. I wonder if this could/would become a popular mod? Open source ETC anyone? ETCguino?:eek:

Have you tried upshifting/downshifting w/ the lock engaged? It might help that "wrong gear" situation.

I mean, if you engaged it in the wrong gear, can you just manually downshift with it still locked up without causing damage?

I wonder if there is a simple way to force a higher gear, i.e. remove kickdown linkage, put check valve in transmission vacuum line, put weaker/stronger spring somewhere in valve body, ???. Then just use the selector lever to choose the gear (and put the lockup toggle switch on the selecter lever)

In stock form it shifts too late (for FE), With the TC lock, it shifts too early for the rpm.
A while ago, I tried loosening the kickdown linkage which just made the shifts slower and soggier. On the Toyotas, tightening it it changes the pressure in the valve body and makes the shifts harder and quicker. Supposedly this reduces wear on the clutches. If tightened, it jumps a bit when you put it in first or reverse gear. It does not seem to change the shift points although I should confirm this with my new tach. The other suggestions, I don't know.

Yes, I can downshift and upshift normally so the wrong gear thing is not a big deal, just kind of embarrassing in a new driver sort of way. There does not seem to be any shift shock at the throttle positions I am shifting at. you can feel it shift more positively but i wouldn't call it shock. Way more "shock" when I downshift in stock form and there is no prohibition against that.

Install a manual shifter and clutch pedal. Wire up the shifter to microswitches where each gear should be, and wire up the clutch pedal to the TC solenoid. Push clutch, shift to another gear, release clutch. Boom, instant manumatic. :)

Clev,

That, my friend is absoludicrous.:cool: I must have one. Manumatic. Sounds like something Mercedes Benz would come up with only they would add an umlaut. The clutch idea, is genius. My left foot is slightly atrophied from under-use anyhow. It should have been obvious but my grasp of the obvious is a little tenuous.

On the way home I was thinking of how to make it ergonomic. What is the best way to do it so you know what gear it's in by feel and so neutral is always handy for instant eoc from any gear. That's probably the best way and it's already learned. The shift lever from an automatic makes you have to slide it all over the place and I have slipped into reverse for a split second a couple of times.:eek::eek::eek:

Anyone know of a good video game shifter? That would already have the microswitches built right in. Heck, my elec-trak has a video game joystick so It'll fit right in.:rolleyes:

how do you switch into neutral without physically shifting the lever
 

i only have two shift solenoids and so 4 gears. will have to do more research.
GREAT IDEA WITH THE CLUTCH PEDAL AND STICK!!!!!!!KUDOS

Hey, there you go. Then you'd have a shifter with short throws that could mount on top of the console.

The general rule, due to the way things are constructed in both types, is that Automatic trannies, you shift hard and fast, and manuals, you shift slow and deliberately.

I know for a fact I can take a brand new transmission and grind gears w/ the clutch fully disengaged, by jamming the synchros. (Shifting like a ricer, with all the torque my arm can put on the shifter) I've broken shifter levers demonstrating how NOT to shift a manual. (Aluminum short throw shifters)

In an automatic, the clutches are allowed to slip so that the gears aren't engaged as quickly. It's an NVH concern that "shift shock" might disrupt the "driving" experience for consumers. If you can get it to shift firmer, take comfort in the added shift shock by knowing that your transmission will last longer than the next guy, because you're not subjecting the clutches to extra wear. Automatics shift into the next gear before releasing the first one, which is why the clutches are allowed to slip. Higher pressure causes the scenario to play out faster, meaning a harder gear engagement, more positive shift feel, and less slippage.

This also equates to less heat generated.

Nice project, orange4boy. If I were doomed... I mean stuck with an automatic, this is something I would definitely pursue.

orange4boy - Dude, you've done it. You've gotten me to look further into it. According to Hayne's, there is an electronic solenoid that locks the TC in my transmission, even though the trans itself is hydraulic, not electronic. I'm going to take a look for the wires in some less-than-visible places under the hood, so I'll update my thread with progress if I make any. Hopefully, I can kife a microswitch from my Father, who works for ShopVac and gets them like they're candy.

Cool beans, daddy-o!

You will love it. My TC lock wire came right out of the main ECU pinout which made it a snap to wire. I hope yours is as easy.

I was grovelling for the oil masters today. I finally changed the ATF today and for the first time dropped fully synth 5-20 into the ICE. The tranny felt much better after and didn't slip as much in first. I'm going to do it again soon because the thing takes 6 qt and I could only drain 2.5. I wish there was a way to drain more. Crap. I just remembered, I was going to try to drain the ATF rad. Oh well, Ill do that next time. Can you do that with low pressure compressed air?

I don't feel nearly as doomed as I did before the switch. Wait... Are there degrees of doomed?

You can actually use the TC to siphon the fluid from your transmission by identifying the pump's output line (to the cooler) and draining a qt from it, then adding a quart back to the fluid's filler neck.

Of course, if you're comfortable pulling the transmission, you could just drain the torque converter. Some have suggested just running it dry in neutral, as well, but I'm not sure I'd practice that way.

When I did the fluid in my wife's Saturn, the torque converter was easy to get to, since the engine was out already. I drained both, then added 7 qts of fluid to the transmission and ran it through the gears for a few mins before taking off for the first time.

Somewhere, there is a dipstick kit for her transmission, and I'm going to get it. It's supposed to be a sealed unit that doesn't require service. (rofl)

My Grand Prix would really benefit from this. At 30mph in 3rd, its at 1050rpm, and accelerates quite well. It has the torque, but it won't hold the gear. Heck, even 4th has the torque to go up the hills around here. I really should do this to my GP, if I can.

Christ, are you talking about Cara or the GP?

Your GP is electronically controlled... as such, you can shift into first, floor it, and never worry about over-revving the engine. It will shift when your tach gets into the yellow/orange area. Neat feature. Granny did the same. Didn't make her any faster, but it still sounded cool!

I'm talking about Cara here, but I researched some on Granny, as well.. I never got around to doing anything w/ Granny, b/c it was the wife's car, and she'd never use it.

I gave Granny to my Father last week because my Wife has the Saturn now, and he needed a spare... no point in making him buy a new to him car when I had an extra, right?

I think that's a "yes, you can". I think most if not all ECTs have a solenoid for TCC lock and most modern autos have TCC lock up.

Ya know what?! I didn't answer the damn question, did I?

Yes, you can manually lock up your GP. The only thing is figuring out what kind of signal your TCU expects to see/give and making the same signal. It's not always as simple as a switch inline, sometimes you need an entire circuit (not necessarily in your case) to mock the TCU's signal.

This is something you'll have to research in places like 60degreeV6.com and other sites.