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1998 T100 SR5 2WD
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Discussion Starter #1
Decided to put this in it's own thread... ;)

Using information from this and this from radesignsproducts.com, I will try to document what you need to know to have manual control of yer A340 automatic transmission fer the T-100. ;)

Looking at the EWD, the colors to the solenoids are:

A340 transmission (5VZFE)
Solenoid #1 = White
Solenoid #2 = Red-Yellow
Solenoid #3 (Lock-up) = Yellow-Black

A340 transmission (3RZFE)
Solenoid #1 = White
Solenoid #2 = Black-White
Solenoid #3 (Lock-up) = Yellow-Black

So tapping into the Yellow-Black wire will give you control of the torque converter solenoid. You could simulate the solenoid's resistance by terminating the ECU end with the proper resistor when you switch over to manual control. This should prevent the ECU throwing a check engine code fer the transmission. :D

Sending 12V to the lockup solenoid will activate the solenoid.

From the EWD, the solenoid resistance is about 13ohms.

Looking through the FSM and the EWD, there doesn't seem to be any splice points in the harness between the ECU and the lockup solenoid. This means you will need to tap into the wiring harness or build an plug/play adapter that would interface between the transmission's solenoid connection and the wiring harness if you don't want to cut into the harness.

A method to disconnect 12V power to the solenoid when the brakes are applied is an idea way to ensure the lockup solenoid is automatically disengaged. If not, yer gonna have to do this manually every time.

An indicator to show the lockup solenoid is in manual mode would be ideal, too.
 

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1998 T100 SR5 2WD
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Looks like it will require a 2 relay setup going by this page from the12volt.com. :D


Going by this post...they have the 2 relays setup differently. I will go with the first relay diagram.

So with a switch, I will switch control from the ECU to the powered relays/momentary switch. The switch will also direct the signal from the ECU to a dummy load (13 ohms) so it doesn't throw a check engine code.

There will be 2 momentary switches, one normally open (momentary button shown in the diagram) to activate the solenoid and one normally open but depressed by the brake pedal in it's normal position (brake switch) in the red circuit between the 2 relays. Stepping on the brake will break the circuit and allow you to disengage the lockup solenoid. You will have to press the Activate button to manually lockup the solenoid once you git to yer gear of choice. This will prevent you from coming to a stop with the torque converter locked and stopping the engine.

There will be 2 LEDs to indicate that the control has been switched from the ECU to manual control and when the lockup solenoid is activated.
 

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nice man but the only thing about 3.0l trucks is i have done this and there isnt enough power for it to make a huge diff. so i considered it a failed experiament :( but it does help when pulling loads well over the limit haha lets say like a tractor and a rhino all on a 24ft trailer haha :)
 

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1998 T100 SR5 2WD
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Discussion Starter #4
Even though it didn't work out fer you...there was one person who was looking fer a solution from about a year ago... ;)
Varithms' thread... :D
 

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not sayin it didnt work just sayin for people who want speed out of it is what i meant but it worked wonders for pullin loads and gas mileage went up about .4mgps for me so all in all worth the relatively small amount of time to do it. oooo and make sure if anyone does this only to do it in 3rd and fourth gear if you do it in either first or second it will be easy to demolish yer tranny over time. and in 1st and 2nd you also run an increased chance of boggin the engine (personal exp) ;)
 

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1998 T100 SR5 2WD
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Discussion Starter #6
Using the 12V automotive relays and sockets (stock colors) I got from AllElectronics.com, this is the setup I came up with...


A switch will direct the feed from the ECU to either the solenoid (stock setup) or the 13ohm 15 watt resistor. This same switch will also direct the feed from the relays to the solenoid when switched from the ECU. The switch will be labeled "Manual TC". ;)

I will insert the "Manual TC" LED in the power circuit and the "TC Locked" LED in the solenoid circuit. :D

Looks like the best place to tap into the solenoid circuit is down by the transmission connector. Wire access will be fed from the rubber grommet by the driver's seat floor pan. The relay setup can be placed under the dash and the switches/LEDs under the coin slots. ;)

Here's how the DPDT (double pole, double throw) switch will be configured...


The yellow wire from the relays will return back to the solenoid leg of the switch. :D
 

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I think keeping 1st and 2nd as auto TC is a good idea as well. Bam could this be adapted to work to do that?
It would also be nice to make it auto TC once speed is below 35 to prevent stalls or bogging
 

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1998 T100 SR5 2WD
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Discussion Starter #8
I think keeping 1st and 2nd as auto TC is a good idea as well. Bam could this be adapted to work to do that?
It would also be nice to make it auto TC once speed is below 35 to prevent stalls or bogging
Well...you can turn on the main switch when you git to 3rd gear and then press the "Activate" button to engage the TC lock... ;)
 

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1998 T100 SR5 2WD
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Discussion Starter #9
Got more parts today...25' of trailer wire fer $12 at Walmart! Should be enough to wire it up as soon as I git the other parts. :D
 

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1998 T100 SR5 2WD
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Discussion Starter #10
Looks like I may not have to cut the wire harness... :D

Using the wire harness internal to the transmission...and the connector from the transmission harness, I should be able to make my own adapter and it should be able to plug right in!

82125B WIRE, TRANSMISSION
82125‑30400 1 $20.68

Haven't found the part number fer the transmission wire harness connector...yet. :(
 

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1995 Toyota T100 DX
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Looks like I may not have to cut the wire harness...


Using the wire harness internal to the transmission...and the connector from the transmission harness, I should be able to make my own adapter and it should be able to plug right in!

82125B WIRE, TRANSMISSION
82125‑30400 1 $20.68

Haven't found the part number fer the transmission wire harness connector...yet.
Any update on this fix?
 

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1998 T100 SR5 2WD
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Discussion Starter #12
Any update on this fix?
Not really a fix but more of a mod. No, I haven't done anything more with this mod as I never built my adapter to hook in between the harness and the transmission connector.

I never did figure out how to easily control the ground fer the relay so when I stepped on the brake pedal, the relay would disconnect manual control of the torque converter. :(
 

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1995 Toyota T100 DX
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Not really a fix but more of a mod. No, I haven't done anything more with this mod as I never built my adapter to hook in between the harness and the transmission connector.

I never did figure out how to easily control the ground fer the relay so when I stepped on the brake pedal, the relay would disconnect manual control of the torque converter. :(
darn cuz this would be key for driving on a 40-45 mph road and having the torque converter lockup so we dont have to deal with the rpms sitting at 2250-2500, kind of a sucky, because with all other cars/trucks i have drivin, the torque converter clutch kicks in at about 40-45mph our doesnt kick in until 51 and you have to have the gas pedal in the right position for it to lock up right away or else you have to manually do it with your foot by letting of the gas and that gets annoying sometimes, sometimes mine doesnt lockup until im going like 60mph
 
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