Manual Torque Converter Lockup

[ripper]

you may have connected the relay the wrong way around. Make sure that the common contact of the relay (30) goes to the solenoid and not the TCU.

You were right. I had terminal 30 feeding power into the TCU, and 87a linked to the lock up solenoid. Can't believe I made such a dumb mistake. After I swapped them over it worked perfectly.

I've damaged the lock up part of the TCU, so now I'll have to manually lock the converter all the time. At least it didn't do any damage inside the transmission, I've had it in and out too many times already.

Having the brake light switch as a cut out for the lock up is really handy. If I was doing it again I might wire it to only work when the system is on. Having the solenoid click every time I touch the brakes was something I hadn't thought about before.

So I owe you big time. First for your efforts with sharing your wiring diagram, and now for guessing what my stupid mistake was. I'm gong to do a full write up of the project, so I'll give you credit in the intro. Thank you.

[taslucas]

Ok it took a bit of finding lol but im bringing up this old thread.

CHAZ.....i hope youre out there mate as you seem to have the expertise i might need.

Ok so im still having the problem where my torque converter locks/unlocks rapidly once im over 85k/hr. Then sometimes only engages/disengages a few times then wont lockup at all and stays at around 2400rpm.
Pretty much everything has been replaced (new TPS, new Temp switch, recently reco'd box [then pulled down and examined thoroughly], Heavy duty Nomad Valvebody from wholesale autos).

Anyway, the question is.... If i fit a manual lockup switch, will the TCU/ECU still try to automatically lockup without me manually switching it? Or will the lockup solenoid only engage when i manually switch it?

[NissanGQ4.2]

Thread has now been moved to the Gearbox sub-section

Cheers

Toddie

[teno45]

Hi TasLucas,

The way Chaz's diagram is wired, you could describe it as "Factory" and "Manual On" modes.

That is, when the additional parts are turned off, it is in factory mode. It will still be controlled via the Transmission Control Unit.
When the dash switch has been turned on, and the foot switch activated, it is Manually on.

Reading between the lines, if you wish to eliminate the Transmission Control Units (TCU) control, all you would need to do, install the circuit as per Chaz's diagram. Except, do not connect the wire from the TCU to the Control Relay.

[taslucas]

Thread has now been moved to the Gearbox sub-section

Cheers

Toddie

Thanks Todd, I just resurfaced the old thread, i have not the power to move it LOL !!

[Chaz]

Ok it took a bit of finding lol but im bringing up this old thread.

CHAZ.....i hope youre out there mate as you seem to have the expertise i might need.

Ok so im still having the problem where my torque converter locks/unlocks rapidly once im over 85k/hr. Then sometimes only engages/disengages a few times then wont lockup at all and stays at around 2400rpm.
Pretty much everything has been replaced (new TPS, new Temp switch, recently reco'd box [then pulled down and examined thoroughly], Heavy duty Nomad Valvebody from wholesale autos).

Anyway, the question is.... If i fit a manual lockup switch, will the TCU/ECU still try to automatically lockup without me manually switching it? Or will the lockup solenoid only engage when i manually switch it?

Thanks teno45, just beat me to it……….

Lucas,
You’re problem may just be a bad electrical connection at one of the plugs to the transmission or TCU. Even a damaged wire that open circuits with vibration could cause those symptoms. Anyway, as teno45 mentioned, if you fit a manual lockup circuit, you should still have factory control if it’s connected up correctly. When the converter isn’t manually locked it should still lock up as it does now when you get up to the correct speed.

[taslucas]

Thanks Teno45, i have an adversity to all electrics!! So it even hard for me to read between the lines!!

[taslucas]

Thanks Chaz.... Ill have to have a good check of all the wiring.
Ive also heard that it may be an earth issue in the lockup solenoid and connecting another earth strap from the box to the chassis may help (bigrig).

EDIT: i have already checked and cleaned the TCU pins/plugs

[Chaz]

Lucas, yes there's a good chance that it may be an earthing issue. I can't remember if the Jatco box engages 4th gear through the temp switch or not, but some 4 speed transmissions do and in that case, you may also have problems getting 4th or dropping back to 3rd if there's a bad earth at the transmission. Anyway, its always good to add another one because I recon you can't have too many earths.

Good luck with it,

[taslucas]

Thanks mate