Nissan Auto

[tuckertrucker]

Hi all, I'm doing a TC Lockup Switch mod and am deviating slightly from the common way of doing it. I've got a 24v Safari running a RE4R03A. Would it be possible to put a relay in series with the lockup solenoid so that I can completely disable it from the TCU, and another from me to engage it manually. I understand that doing it this way would render the P/N protection useless as I'd still be able to energise the solenoid manually, but I'm sure I could find a solution. But is this possible? Or will a set up like this trip a fault in the TCU or cause voltage drop to the solenoid or anything else I'm neglecting?
Cheers, Dylan.

[growler2058]

OY Chubba, didn't you just do something like this?????

[jff45]

Have you done a schema of what you plan to do?

If you look closely at the original schema, you'll see that manually locking the TC will disconnect the TCU from the lockup solenoid because, if you don't, it will send power into the TCU at the same time.

I did a system with a Jaycar frequency switch that negates the need for the P/N safety switch. I set it so I can only lock up the TC above 60 kph. It connects to the VSS (pin 40) on the TCU.

[jff45]

Here's the schema for my TC lockup system.
Note that the control relay must disconnect the TCU when it's manually locked.

...

[Chubba]

OY Chubba, didn't you just do something like this?????

Yeah I did but my set up isn't as sweet as jff45. He knows more than me. I just have the one relay that is normally closed so the TCU works as normal with the lock up until I flick the switch and I put power to the lock up. A normally open relay would completely cut of all power from the TCU to the lock up at all times. But I wouldn't know how that would affect all other functions of the trans.

[tuckertrucker]

If you look closely at the original schema, you'll see that manually locking the TC will disconnect the TCU from the lockup solenoid because, if you don't, it will send power into the TCU at the same time.


Couldn't a power diode solve that issue?

[jff45]

What issue? If you wire your control relay to keep the factory lockup circuit closed through the NC contacts (as Chubba also mentioned above) you don't need to start adding diodes.
Opening that circuit to manually lock the TC through the NO contacts has no adverse effect on the TCU - many people have been doing it for years so it's a tried & tested method.

I have a small LED on my pillar pod that tells me when the TCU has locked the TC and I often manually lock while it's in that state which means I'm switching from TCU power to alternative power when the relay activates and it doesn't cause any issues or throw any codes.

Without seeing a schema of what you want to do, it's hard to give any advice.

[tuckertrucker]

Have you done a schema of what you plan to do?

If you look closely at the original schema, you'll see that manually locking the TC will disconnect the TCU from the lockup solenoid because, if you don't, it will send power into the TCU at the same time.

I did a system with a Jaycar frequency switch that negates the need for the P/N safety switch. I set it so I can only lock up the TC above 60 kph. It connects to the VSS (pin 40) on the TCU.

This is what I've been thinking. The 1st switch allows me to deactivate the TCU's control, meaning I can unlock the TC when the TCU has it locked. The momentary switch allows me to lock it while my foots on the switch, and the dashboard switch locks the TC and leaves it locked until either I unlock it or shift into P/N when that relay will disable the system. I wanted the first switch so that I could stop the TCU telling the TC what to do, also so I can unlock the TC when needed (ie open road in OD when I need more power but dont want to kick down). I don't really want the brake pedal to unlock the TC so I left that out.

[tuckertrucker]

What issue? If you wire your control relay to keep the factory lockup circuit closed through the NC contacts (as Chubba also mentioned above) you don't need to start adding diodes.
Opening that circuit to manually lock the TC through the NO contacts has no adverse effect on the TCU - many people have been doing it for years so it's a tried & tested method.

I have a small LED on my pillar pod that tells me when the TCU has locked the TC and I often manually lock while it's in that state which means I'm switching from TCU power to alternative power when the relay activates and it doesn't cause any issues or throw any codes.

Without seeing a schema of what you want to do, it's hard to give any advice.

Good point, misread the post - need my glasses. I've just uploaded a picture of what I'm hoping to do. Cheers

[jff45]

If you have it locked with 3, you won't be able to get to the point where you can put it into Park to deactivate it because it will stall. It will be the same as stopping with a manual gearbox without depressing the clutch.
You need a brake cutout as shown in the original schema Chaz did.

I don't understand why you would want 2 if you have to keep your foot pressed on the switch to keep the TC locked.

[tuckertrucker]

Wouldn't that just be a matter of remembering to unlock it? I didnt want the brake switch because part of my wanting this was for engine braking on decents, and in the case that Im loaded and the engine is braking sufficiently I'd still like the service brake as well. Unless I put the brake cutout in and have a dash switch to disable it when I don't want it?
As for the foot switch, I wanted something I could temporarily press for a short period of time. But I've actually done away with that as I realised it was a bit pointless.
Thanks for your help :)

[jff45]

Yes, you'd have to remember to unlock it.
The foot switch in the original schema is designed to keep the TC locked for engine braking and using the brakes as well has no effect in that case.

The reason I later designed mine with the frequency switch was because I got tired of the lockup being switched off in running traffic when you just need to briefly touch the brakes to keep a distance or whatever.
I also don't need it under 70 kph so the speed dependent system allowed me to remove both the brake switch option and the Park/Neutral safety (which I devised and got added to the original idea)

[tuckertrucker]

I adapted the original schema to to get rid of the brake switch and adapt the foot switch (which Ive done away with), but still wanted lockup at lower speeds. I've read through your job thread and it seems pretty understandable. Just hope my final idea works aye.
So if Im reading your schema correctly, your narva switch arms the system, and the push button locks the tc, and pushing it again breaks the circuit and unlocks the tc. But the whole system will only feed power to the first relay at or after 60kph. Doing away with the brake switch and relay. But you cant lockup under 55kpm?

[tuckertrucker]

I've also considered using a three way switch for the manual lockup/ auto lockup/ unlock idea I had. Thats the #1 switch to manually unlock the tc. The idea of that is to be able to select between unlock, auto and manual in one switch. Thoughts on that?
I went with the unlock idea cause in certain scenarios the lock is inconvenient, or atleast the TCU lock is. Eg, It doesn't unlock in OD by gassing it but rather kicks down to drive and screams, when all I'd like is a little more revs in OD to get going (say stuck behind Nana on motorway doing 80 and go to pass her, I don't need drive if I could unlock).

[jff45]

No, the pushbutton only activates it. To deactivate before speed falls to 55 kph, you switch off with the Narva switch. The speed threshold is adjustable in the frequency switch. I rarely use it below 70 kph.

I've found with mine that any quick use of the accelerator that causes a sudden change in the TPS reading will immediately unlock the TC anyway if it isn't manually locked. This is the reason the manual TC lockup was devised, because it too readily unlocked and caused unnecessary heat build up.

Anyway, everyone is free to do it as they like for their personal preferences and you can always modify it later if it doesn't work as expected.

[tuckertrucker]

Oh I see now. I'm a little new to reading relay schematics. Haha.
In my Y60 the TC will unlock in OD with any quick depression of accelerator, but within seconds itll lock again, or kickdown to third. It also doesnt lock in any other gears if the OD botton is off - id like some lock in drive.
Thanks for your help, I'll see about this design of mine, and if I start stalling it around town...... I'll have a look at your frequency switch. Its a good way of avoiding the unneccassary embarrassment aye.
The Y60 Safari's in NZ are all 24v. I suppose there's a voltage reducer before the TCU and ignition right, ill get a tester on it later but I'd expect a recuder cause the instrument cluster and stereo are both 12v.

You seem to be the god of this topic 'round here so if I run into any troubles or queries Ill PM you if thats alright? Or just post it in here?

[jff45]

PM is fine, happy to help.

Shame you're not local, I'm about to throw out low mileage 24v starter & alternator from my imported Safari TD42T..

[tuckertrucker]

a shame alright. Ive just recently had to reco my alternator, damn thing wouldn't charge over 23v, Id start the truck once and that'd be it.

[Chubba]

In my Y60 the TC will unlock in OD with any quick depression of accelerator, but within seconds itll lock again, or kickdown to third. It also doesnt lock in any other gears if the OD botton is off - id like some lock in drive.......

Don't know about GQ but GU does lock up in 2nd, 3rd(Drive) and OD. As long as all parameters are met. ie. speed, revs, torque ect.

[tuckertrucker]

I'd have thought they'd be the same. They both run the RE4R03A don't they? Mind you the TCU is different. It seems to lock up in those gears only if the OD breaker is closed. But around the burbs and lower speed areas where I don't use the OD, where is have the breaker open, it wont lockup. One of my main reasons for this job.

[tuckertrucker]

When I drive around, I tend to have the E-A/T switch in hold and manually select the gears. Is this bad for the trans? And for when I've got the lockup switch in, is it advised not to be locked during gear shifts? Just hoping I'm not destroying my trans, so far its been bullet proof.

[jff45]

It's strongly advised not to have it locked during shifts. I would even advise to not be accelerating or under any kind of load when you lock it. There's a reason that the factory design engages the TC clutch softly by gently increasing the voltage.

[tuckertrucker]

Thought so, but what about the E-A/T switch? Using it I can pretty much have manual control as it wont shift unless the vehicle and engine speed are too high or too low for that particular gear.

[jff45]

I believe the Hold position starts in 2nd gear and is designed for slippery conditions to try to minimise wheel spin.
In the 8 years that I've owned my vehicle, I've never used it.

[taslucas]

I believe the Hold position starts in 2nd gear and is designed for slippery conditions to try to minimise wheel spin.
In the 8 years that I've owned my vehicle, I've never used it.
That's interesting.
I kind if thought it held the gear longer like the power button but on deceleration... Though I have no proof this is the case lol

tappin from tassie

[Chubba]

When I drive around, I tend to have the E-A/T switch in hold and manually select the gears. Is this bad for the trans? And for when I've got the lockup switch in, is it advised not to be locked during gear shifts? Just hoping I'm not destroying my trans, so far its been bullet proof.

Hold button doesn't hold it in gear longer. It will only allow the trans to drop to 2nd. Not a good idea to drive around town with hold button on. This will mean you are starting in 2nd from all stops. Extra stress on trans not needed. Hold button only for 4wd low range in extra slippery conditions and for some 2wd high range situations where you want foot to the floor power but don't want it screaming in 1st.

[tuckertrucker]

Hold button doesn't hold it in gear longer. It will only allow the trans to drop to 2nd. Not a good idea to drive around town with hold button on. This will mean you are starting in 2nd from all stops. Extra stress on trans not needed. Hold button only for 4wd low range in extra slippery conditions and for some 2wd high range situations where you want foot to the floor power but don't want it screaming in 1st.

Yeah I thought that, but thats why I use the stick to select the appropriate gear. As in Low, 2nd, Drive and OD.

[tuckertrucker]

On the 1992 RE4R03A transmission, am I correct in saying that the TCC solenoid is on pin 22 of the TCU harness, and the P/N Inhibitor is on pin 19. I've looked around and have got multiple answers. Ill get a meter on them tomorrow when I do the job just to be sure (could be fun testing the TCC pin cause I'll need to be in OD to get lockup.....) but any information would be great.
I understand there are differences between the 88-94 transmission and the 99-01 and others?
Cheers,

[jff45]

Can't help you with the TC lockup pinout but the Park/Neutral wire will have 12v in either of those positions.

[tuckertrucker]

Finally did it!!! This morning I put a meter on the TCU pin 22 and found that the TCC solenoid has +12V power when the ignition is ON, and +24V when it is locked. Pin 19 is the Park/Neutral signal from the inhibitor switch and powers +24V when park or neutral is selected.
I took 24v from the cigarette lighter to the switches on the dash, and I earthed the relays to the body where the TCU bolts up. I used 24v 30A SPDT relays from Jaycar and an inline 10A fuse between the power and the switches. I used two toggle switches to achieve Auto/Unlock and Auto/Lock. With this set up I can disable the TCU from locking the TCC with one switch (which will unlock the TCC), and I can also manually lock the TCC. Works like a dream too, got it first time. If I "unlock" the converter, the TCU wont lock the converter, and I can still manually lock it. If I leave the first switch on auto, the TCU can still lock up but I can also lock it. Just now waiting on the plastic cover for the switches to fit into the dash in, at the moment theyre just hanging on the center console.
The only thing I wasn't expecting was the 24v. I was thinking the TCU was running on 12v from a reducer, but its definately 24v, and feeding 24 to the TCC and P/N inhibitor.
I hid the relays away in a neat little black box and fitted it above the TCU in behind the passenger kickboard. Neat and tidy. Just got to remember its locked when I lock it, hahah. Ill be the only person in NZ who has ever stalled an auto.
Thanks heaps everyone for your help and advice on this one!!
Cheers, Dylan.