Patrol GQ auto convertor lockup

[boggy2006]

hi, I found this link with information about manual torque convertor lockup on a GU Patrol. Is the wiring the same to the GQ patrol TCU? (Same pins/wire colour)
http://www.chaz.yellowfoot.org/Lockup%20Trans%20Switch.htm
Thanks

[Chaz]

Hi Boggy,
No it's not the same. I think from memory the Y60 used pin number 21 on the TCU for the lockup solenoid. You would need to check it with your manual because some other models were different also. The circuit will work on a Y60, but you can't lock your converter in 1st gear unless you use a GU valve body. In some ways thats better because you don't have to worry about the brake pedal release to unlock it unless you have the HOLD switch on.

[boggy2006]

hi, that's great thanks, I'll look into it.

When you say that it can't be locked up in 1st, does that mean if I try to it will break it, or it just won't lock up even if the lock up solenoid is active?

[Cadbury]

Hi all
Does this prevent run away on a steep down hill,
If so can you do this to a 1999, 4500 auto bow?
Cheers
Cadbury

[YNOT]

hi, that's great thanks, I'll look into it.

When you say that it can't be locked up in 1st, does that mean if I try to it will break it, or it just won't lock up even if the lock up solenoid is active?

It just wont lock up in first, it wont damage anything.

Tony

[YNOT]

Hi all
Does this prevent run away on a steep down hill,
If so can you do this to a 1999, 4500 auto bow?
Cheers
Cadbury

Yes it does reduce runaway and yes it can be done on a '99 4.5 auto.

Tony

[boggy2006]

That's good, thanks. I guess it means it won't stall the engine then when stopping in 1st with it locked up. What happens if you try to drive through the gears normally (with it in D) with it locked up all the time? Would it work? Do I have to try it ;-) ?!!

ps. according to the workshop manuals on here, it looks like pin 22 for the GQ. Pin 21 is the overun solenoid with only activates in 1st, 2nd, 3rd which I beleive is why the revs drop and it virtually free wheels when you take your foot off the accel in 4th. Might be nice to have that operating in 4th too.

I'm also wondering if there's anything that can be done with my sloppy 2nd-3rd change. Firstly checking the shift A and shift B solenoid coil resistances and when they operate during the 2nd-3rd shift, if they are PWM'd etc.

[the evil twin]

That's good, thanks. I guess it means it won't stall the engine then when stopping in 1st with it locked up. What happens if you try to drive through the gears normally (with it in D) with it locked up all the time? Would it work? Do I have to try it ;-) ?!!

ps. according to the workshop manuals on here, it looks like pin 22 for the GQ. Pin 21 is the overun solenoid with only activates in 1st, 2nd, 3rd which I beleive is why the revs drop and it virtually free wheels when you take your foot off the accel in 4th. Might be nice to have that operating in 4th too.

I'm also wondering if there's anything that can be done with my sloppy 2nd-3rd change. Firstly checking the shift A and shift B solenoid coil resistances and when they operate during the 2nd-3rd shift, if they are PWM'd etc.

Hi Cobber,

I did this mod to mine and subsequently a couple of others and it was one of the best things I did to the old girl.

To clear up a few things...

Firstly... the TC will lock in first gear but unlike the GU's that will stall if you come to a complete stop the GQ has a lower pressure valve body and will "buck" a little bit but not stall however still not a recommended practice. Braking to a complete stop with it engaged that is.

Second... ECU pins. You are correct it is pin 22 for all the GQ's I have done but the wire colour code changes between a few models. See my posts here: patrol4x4.com/forum/nissan-patrol-gq-y60-ford-maverick-11/94-gq-auto-tranny-lock-up-switch-8860

NOTE: Direct link removed as patrol4x4 are currently experiencing virus / malware issues, view the link at your own risk.....Regards, Forum management

Third... there are pics floating around that have the Engine and Tranny ECU locations mixed up. The Tranny ECU is behind the passengers kick panel in the LH side of the Pass footwell, well, again at least in all the GQ's I have done. The best spot to put the relay IMHO is above the ECU so do that while you are in there

Now for the advantages/disadvantages

Advantages and a couple of them are BIG ones IMHO
1. Heaps better engine braking in downhill descents off road.
2. Significantly lowers Gearbox Temps when towing as the TC slippage is one of the main heat sources
3. It sort of gives you split gears between Drive TC locked and Drive TC unlocked (esp when towing) and same for O'drive so makes the hills easier to negotiate on the open road.
4. Better fuel economy on-road in daily driving if you do a lot of 70 to 80 KPH stuff.

Disadvantages only minor IMHO
DON"T lock up the TC under power IE lift the pedal and lock it or lock it prior to descent.
When locked you drive it like a manual tranny and again just lift the pedal momentarily as you change gears. There is no need to disengage the TC lockup if you do that, you can just leave it locked and only disengage when stopping.

ET's thoughts
I reckon it is a cracking mod and can be done for under $20 depending on how "techo" you make it with brake realys speed sensors etc adding to the cost. It totally changed my truck and I did the best part of 100,000 K's touring, towing the Camper and 'wheeling with no issues whatsoever

I just had an old floor mounted "dip switch" for the left foot to engage/disengage, a single pole switch on the dash to "arm" the floor switch and a 12 Volt LED under the switch to tell me if it was "locked"

Finally... Kudo's to Chaz for putting the idea and original circuits up.

[boggy2006]

Thanks for the info. It would be great if it was possible to detect a shift then release lock up for the shift, I wonder if shift solenoid A and B could be monitored and used to detect a shift, if they are responsible for the shifts. Also need vehicle speed below a certain value eg. 15kph, then remove lock and revs above a certain value eg. 1800rpm, to engage lock, how about a paddle shift!! Might as well make another ECU whilst I'm at it LOL!! Could do it as I'm an electronics engineer, but it's just finding the time (screaming wife/kids, full time job, not enough holidays etc etc!!).

[ripper]

ET's thoughts
I did the best part of 100,000 K's touring, towing the Camper and 'wheeling with no issues whatsoever


Old thread I know, but were you towing the camper in D or 4th?
Just trying to work out how much weight you can safely tow in OD.

[the evil twin]

Old thread I know, but were you towing the camper in D or 4th?
Just trying to work out how much weight you can safely tow in OD.

As soon as I cleared the town 80 zone I would lock it up and go from there.
Along the flat or shallow downhill was all in OD with the TC locked.
Slight uphill I would drop the OD out and stay locked in Drive
Steeper uphill and I would switch off the Lock up and let the Tranny work normally and lock up as soon as the load was off the engine.
Steeper downhill or coming into lower speed zones if engine braking required I would leave the TC locked and just work back thru the gears.

[ripper]

Thanks, that gives me a bit to work with.

[the evil twin]

Thanks, that gives me a bit to work with.

I should add that mine was a series 2 running 33's and I would usually have the Tranny mode selector in "power" but 90% of the time select the gears myself IE I'd be looking for a change down/up before the tranny ECU would be.

[ripper]

Okay, thanks.

[Kiwiape]

I know this is a very old thread, but someone may be able to help. My Safari (import to nz) is a 96 td42t auto with 95 in big numbers on the tcu. Safaris in nz are generally 24v although mine is 12v like a nz new or oz patrol. It does not have a pin 22 wire if the way I am counting is correct... top right down the first block of pins, and then top left down so pin 22 would be the bottom left pin on the top group of wires. Is this right? The whole setup is in and tested with just the solenoid wire to connect, can't wait to use it! Thanks in advance

[ripper]

My Safari (import to nz) is a 96 td42t auto with 95 in big numbers on the tcu. It does not have a pin 22 wire if the way I am counting is correct... top right down the first block of pins, and then top left down so pin 22 would be the bottom left pin on the top group of wires. Is this right?

Here's the pin chart I used. Does yours look the same?
http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=15663&d=1335615282
Before I cut the lockup solenoid wire, I went for a drive with a test light on that wire to make sure it was the right one. Easiest way I know of to get a connection for the test light into there is to stick a sewing pin through the wire and then put the test light on to the pin.

[Kiwiape]

Thanks ripper, but no. It has one big blue plug with a bolt holding it in place. Your method is how I am testing for the correct wire, but I am unsure as to what volts the correct signal should give unlocked and locked...

[ripper]

Mine feeds 12v out when the lockup solenoid is working, and zero when it's unlocked Kiwiape.

[Kiwiape]

Great, that's what I was hoping to hear. There have been reports of indicator leds glowing weakly while unlocked, indicating a low voltage signal. I'll just disregard that and look for the locked signal and hope it's the right wire...

[Kiwiape]

80695 this is what I have

[ripper]

That's a lot easier to access than the wiring in ours. Ours plugs in near the floor, not the door.

Hope it goes well for you Kiwiape.

[Kiwiape]

Cheers I'm sure it will. I did find another with the same tcu, in Ukraine...haha