Lock up converter?

Pikeman

Pikeman

New member
I am new here and have a 98 3.4 with Auto tranny. I am wondering if it has a lock up converter? If so can a manual lock-up switch be installed? I have done this on a 700R4 in a hot rod, but would like to do it on my runner to help in steep downhill kinda like the Downhill assist control on the 4th gen with out the EBC added. Thanks and lots of good info as i have seen on other threads.
 
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I remember that trick from the Grand National crowd. I just did some research on the this for 3rd gen. I'm not positive when it locks from the factory, as the only info i have on the toyota auto trans is from the autoshop101 website, which states it locks above 37mph, and in high gear. This is general toyota info though, so not sure if the 4runner is exactly the same. i would probably want to do a little bit of research on this before spending the time to modify it.

As far as doing the modification, i do have the wiring diagram for the 00 4runner, if you don't have a 00, then i suggest spending the $10 on a day pass for the TIS website, anyway the wire can be found at the engine ECU, terminal #9 and is listed as green w/ red stripe. It should be a Positive trigger. If you want to do it at the transmission side, it is listed as a yellow wire in terminal 3.

This would be an interesting project, if you have time to play w/ it before i can keep us posted!
 
Basically the TC works off of inertia and allows slipping. With a lock up converter it acts more like a clutch to help with fuel economy usually once at a set speed on fwy. A manual locking button would allow you to engage it(eliminating the slip) when you want such as downhill to utilize more engine breaking like you would have with a manual transmission. I was hoping that maybe someone had already done this but if I need to be the first I will keep you posted.
 
Wanted to know if anyone has installed or understands how to install a switch to interrupt the torque converter lockup on a 1998. I don't want it to lock under some circumstances, so would be looking to interrupt the 12V signal that would normally tell the transmission to lock up while in 4th. I would be doing the opposite of this thread, not looking to manually lock, but instead a switch to manually keep the torque converter engaged and not lock up.

I think it would just simply be installing a toggle switch and interrupt the wire that sends the lockup signal. "On" would keep the signal intact for normal transmission function. "Off" would interrupt the signal and keep the torque converter from locking up.
 
gamefreakgc said:
I think it would just simply be installing a toggle switch and interrupt the wire that sends the lockup signal. "On" would keep the signal intact for normal transmission function. "Off" would interrupt the signal and keep the torque converter from locking up.
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Ur right. the ecu can tell when something is messing with the lock up and completely disable said (no more lock up), u have to turn the vehicle off and restart to retest the ecu.
 
Pikeman said:
Basically the TC works off of inertia and allows slipping. With a lock up converter it acts more like a clutch to help with fuel economy usually once at a set speed on fwy. A manual locking button would allow you to engage it(eliminating the slip) when you want such as downhill to utilize more engine breaking like you would have with a manual transmission. I was hoping that maybe someone had already done this but if I need to be the first I will keep you posted.
Click to expand...


I made a drawing a few years ago and posted it using the brake as a unlatch so you don’t stall.


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I did some snooping in the FSM and it looks like the "SL" solenoid (not S1 or S2) is the one that controls the torque converter lockup function. Does that seem correct? I can't remember if the solenoids have a single wire or two wires running to each, it's been a long time since I had the transmission opened up.
 
gamefreakgc said:
I did some snooping in the FSM and it looks like the "SL" solenoid (not S1 or S2) is the one that controls the torque converter lockup function. Does that seem correct? I can't remember if the solenoids have a single wire or two wires running to each, it's been a long time since I had the transmission opened up.
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They have a single wire & as memory serves SL is correct. This is whats inside ur trans:

a340 (2).jpg
 

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Has anyone made a lockup for their 3rd gen? I bypassed the radiator for the tranny and send it through a separate K&N cooler which is kind of small. Most of the time it's fine but when I go up steep hills at moderate to low speeds it overheats fast. On my last trip it briefly went up to 230 F, but usually I'm at 190 or below. What's interesting is that at 80 km/hr or above, going up a hill it locks up by itself when I hit Overdrive Off and ETC. But not at lower speeds so I want to manually force lockup then.
 
Mark_BC said:
Has anyone made a lockup for their 3rd gen? I bypassed the radiator for the tranny and send it through a separate K&N cooler which is kind of small. Most of the time it's fine but when I go up steep hills at moderate to low speeds it overheats fast. On my last trip it briefly went up to 230 F, but usually I'm at 190 or below. What's interesting is that at 80 km/hr or above, going up a hill it locks up by itself when I hit Overdrive Off and ETC. But not at lower speeds so I want to manually force lockup then.
Click to expand...


I have a dead man switch to manually force lockup but with that said I use very sparingly and carefully when maintaining consistence-ish RPM when wheeling/offroad and occasionally for town driving when its hot outside and not able to get up to speed for long periods for the ECU to engage said. I use a dead man so I don't forget to disengage and damage the TQ. I also have extra Transmissions and can replace said without to much issue, only making this point because u can damage ur trans messing with said. the ECU can tell when u r manual messing with lockup and will completely turn TQ lockup off... U have to turn the vehicle off and restart to clear said from the ECU and it will restart lockup as norm
 
Mark_BC said:
Has anyone made a lockup for their 3rd gen? I bypassed the radiator for the tranny and send it through a separate K&N cooler which is kind of small. Most of the time it's fine but when I go up steep hills at moderate to low speeds it overheats fast. On my last trip it briefly went up to 230 F, but usually I'm at 190 or below. What's interesting is that at 80 km/hr or above, going up a hill it locks up by itself when I hit Overdrive Off and ETC. But not at lower speeds so I want to manually force lockup then.
Click to expand...
I'm not sure what speeds you are going, but have you tried turning over drive off (if it's street driving) or shifting into 4 low (if it's offroad driving)?
 
Yes, OD is off. It still overheats in 4L. Basically, anything less than the 80 km/hr or so, the computer seems to stop lockup. I'd like to be in 2WD 2Hi and put it in 2nd and have it lock up. Similarly for 1st in 4Lo.
 
Mark_BC said:
Yes, OD is off. It still overheats in 4L. Basically, anything less than the 80 km/hr or so, the computer seems to stop lockup. I'd like to be in 2WD 2Hi and put it in 2nd and have it lock up. Similarly for 1st in 4Lo.
Click to expand...
Getting a larger cooler with a bypass valve would probably be the best solution vs trying to force the torque converter lockup in my opinion.
 
Mark_BC said:
Yes, OD is off. It still overheats in 4L. Basically, anything less than the 80 km/hr or so, the computer seems to stop lockup. I'd like to be in 2WD 2Hi and put it in 2nd and have it lock up. Similarly for 1st in 4Lo.
Click to expand...
On my 2000 it isn't speed that affects the TC-lock, it's the transmission gear. It only locks in 3rd and 4th. And it never locks in any gear in 4Lo (BTW, when in 4Lo, you cannot get 4th gear.)

As has been stated, "O/D off" keeps it locked up longer when in 3rd and 4Hi, with no effect in 4Lo that I can tell.
 
It would be nice if there's some wire I could splice a switch in rather than installing another cooler + fan etc. etc.
 
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