TD 4.2 automatic gearbox problem

hi everyone
ive just registered to this website, i think it could come in handy.

my gq patrol has an auto gearbox.
usually on freeway or over about 80km/hr the engine revs drop a little and it takes an extra gear, but recently it stopped doing that.
now the revs stay high and to push 100km/hr on freeway has become impossible without the revs being high and high boost. the engine sounds like its having a hard time at that speed.

ive taken it to a number of transmission places and theyre all telling me that its something to do with the lockup solenoid or the lockup cylinder,?? im not sure what any of these are but im just worried that it might end up being a big job.
i was wondering if anyone has heard of this same problem and would have a solution

only reason i havent left it at an auto transmission place is because im worried that they may tell me all these things that are wrong and end up charging me heaps of money..


if someone coul give some advice i would greatly appreciate it
thanks
ramy

G'day mate and welcome aboard - great people, information and laughs to be found on here, so join in to make the most of it!!!

Yep, it's a lockup issue on the torque converter ... having the same problem on mine right now. Could be the lockup solenoid, the temp sensor in the valve body, the TPS, or another gremlin causing it, so not sure that anyone can tell you what it is without some investigation. It's definitely an auto specialist job though mate, but more than likely not an 'overly' expensive one depending on what's causing it ...

Where are you based?? There's a few different places that members could recommend depending on your location.

I'd be going its either the temp sensor or the TPS as thats where I've gotten to (replaced my TPS and didn't resolve though - grrrr) but Taslucas had the same issue I believe and replaced the temp sensor to resolve (can you confirm Lucas? Thanks boss). That's my next path, and from what I understand, the part isn't that expensive, just the labour to remove the valve body and replace.

Enjoy!!

Convert to manual.. just a thought.

Hi mate. Yep I've had a similar problem. My lock up was engaging and disengaging rapidly on the hwy. While yours sounds to be not engaging at all. I replaced the TPS, torque converter, fitted an aftermarket valvebody. Last thing I did was replace the temp sensor and it was fixed bit only for a month. I only used a second hand temp sensor so I'm hoping that by replacing with a new one it will be fixed. I'm currently waiting for the new temp sensor to arrive.
Theres a bit of info regarding this around the forum. Also you could look st my thread in members rides "tasLucas's tb42 ti"

Ps. Keep the auto, they are WAY BETTER FOR 4WDING.

tappn it

What do you guys mean by TPS (throttle position sensor?) Do the diesels have these or are they set up a differeny way? It definitely sounds like a lock up issue as others have stated is normally a trans pro job as it can require certain tooling.

Well, the following depends on how much fault finding you want to do but...

Access the Tranny ECU behind the passenger kick panel.
Locate pin 22 and strip a bit of insulation back then using either a multi-meter or an LED or test lamp take the vehicle for a drive.
The solenoid power should appear on pin 22 (above 85 kph etc etc) if it doesn't then it is an input IE, Temp, TPS, Speed etc
If the power is there above 80ish KPH then it is a transmission issue IE lock up solenoid or whatever

You can also measure the continuity of the solenoid to see if it is burnt out but I can't remember what it is supposed to be, sorry.

If you want any second hand parts I have the lot out of mine which i converted to manual

Hey Guys sorry I've been a little busy and haven't had a chance to check up on the replys..


Thanks heaps for all that info I really appreciate it
I had the lock up solenoid changed last week at an auto transmission place in Fairfield
Which was closest to me.. I live in parramatta nsw for those who asked... But that didnt fix the problem but he noticed that my temp gauge was sitting on cold for long periods and not moving so he assumed that the temperature sensor was buggered and not allowing the computer to read that the engines warm
Enough to engage lock up.. I think that's what one of you guys said in a post???
So I changed that and got back my regular temperature reading.. Which is always hot as we all know haha but... No it didnt fix my problem!

So anyways I think I'll go ahead n try some testing as u all said and go from there..

Thanks heaps guys again and hope you all had a great Easter!!
All the best


Ramy

Good luck with this. Let us know how you make out

Quote:

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Originally Posted by the evil twin

You can also measure the continuity of the solenoid to see if it is burnt out but I can't remember what it is supposed to be, sorry.

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I can probably find this spec if you want to test it. Recently solved a very frustrating problem with ours (randomly losing 1st and 4th gear), and I learnt how to use the AT section of the Nissan workshop manual fairly well.

Quote:

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Originally Posted by the evil twin

Well, the following depends on how much fault finding you want to do but...

Access the Tranny ECU behind the passenger kick panel.
Locate pin 22 and strip a bit of insulation back then using either a multi-meter or an LED or test lamp take the vehicle for a drive.
The solenoid power should appear on pin 22 (above 85 kph etc etc) if it doesn't then it is an input IE, Temp, TPS, Speed etc
If the power is there above 80ish KPH then it is a transmission issue IE lock up solenoid or whatever

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This would work well in narrowing down what needs testing, as would a manual lock up system.
Ours wont stay locked in with the TCU computer, but when I hit the switch myself it works every time.

Hi guys sorry
One more thing
Where can I buy this temp sensor that's accessible once the pan has Been removed

Cheers!

I think you have to buy a genuine Nissan temp sensor, but taslucas would be able to tell you for sure, as he bought a new one very recently.

Quote:

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Originally Posted by the evil twin

Well, the following depends on how much fault finding you want to do but...

Access the Tranny ECU behind the passenger kick panel.
Locate pin 22 and strip a bit of insulation back then using either a multi-meter or an LED or test lamp take the vehicle for a drive.
The solenoid power should appear on pin 22 (above 85 kph etc etc) if it doesn't then it is an input IE, Temp, TPS, Speed etc
If the power is there above 80ish KPH then it is a transmission issue IE lock up solenoid or whatever

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A good suggestion for this sort of thing was to get a sewing pin and stick it through the wire you want to test. I managed to do it with the point of a test light recently but it wasn't easy. Wish I'd read the pin idea before I did it the hard way.

Hi mate, I had to get a genuine temp sensor from Nissan. It took two weeks to arrive and was about $110. Make sure you know exactly which one your after as there are two in each box and theres about 10 different ones depending on the year etc. They ordered the wrong one for me so i had to wait another two weeks. Also, their computer system said that there was only one temp sensor in my box, you could see the one i needed on the screen but when they clicked on it,the system said that it was not elligible for my car! (even with the VIN put into the computer). They emailed Nissan Head quaters and sorted it out.

P.S. Todd might like to move this thread to the Engine and drivetrain section under the sub-section of gearboxes

Taslucas
I am watching keenly because my box won't stay locked either. I put a gu engine into a zd30 gu auto that was working fine so I know it is nothing inside the box. It must be a tps or external something??
Owen.

Quote:

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Originally Posted by PattyWgnOwen

Taslucas
I am watching keenly because my box won't stay locked either. I put a gu engine into a zd30 gu auto that was working fine so I know it is nothing inside the box. It must be a tps or external something??
Owen.

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Yeah I've replaced just about everything so far! Mine locks/unlocks rapidly. If I drive it for a while it'll start off fine, then slowly get worse (locking/unlocking) until it gets to the point where it won't lock and just stays in 4th.

Tap, crackle, pop

I have a theory!!!!! And yes, someone else told me !!! lmao

I'm going to run an earth strap from the box to the chassis direct - apparently this is prevalent in many other cars but not on mine ... getting the wiring covered in water, mud and crud over time has the ability to play with it as such, and apparently the solenoid lockup voltage is similar to the dizzy module only needing around 5 volts with only a mild change to this (plus or minus 10%) being able to cause issues ...

It's a wild one, but I'm going to try it and let you know ...

My shudder whilst cold is not the TC as it turns out - its the seal. When cold, it's letting oil through until it heats up and expands - hence only shuddering when cold due to loss of oil pressure ... hopefully that simple, and again, I'll let you know so all the info is on this thread ...

Still ... I LOVE my auto!!!!

F yeah, I'll give that a go!

Also, which seal are you talking about? The TC shaft seal?

Tap, crackle, pop

Ahhh the old not getting earth trick...
Damn those rubber mounts eh!

Quote:

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Originally Posted by Bigrig

apparently the solenoid lockup voltage is similar to the dizzy module only needing around 5 volts with only a mild change to this (plus or minus 10%) being able to cause issues ...

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That doesn't sound right for a GQ.
Page 66 of the AT service manual says terminal 22 (torque lock-up) of the TCU should be between 8 and 15 volts when the converter locks, and 1V or less when it's not locked.

The earth strap might still help though.

Quote:

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Originally Posted by ripper

That doesn't sound right for a GQ.
Page 66 of the AT service manual says terminal 22 (torque lock-up) of the TCU should be between 8 and 15 volts when the converter locks, and 1V or less when it's not locked.

The earth strap might still help though.

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Hmmmm ... thanks mate ... that in itself may explain the problem. Getting a voltage drop maybe? As I'm sure it was 'measured' with the lockup switch selected and it was only around 5 volts?? Need to confirm this though ...

If you're only getting 5V at the transmission, then yeah, I'd be checking why it's so low.

Quote:

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Originally Posted by ripper

If you're only getting 5V at the transmission, then yeah, I'd be checking why it's so low.

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Thanks boss - as said, need to confirm, but this was the number rattled off to me... fingers crossed ... then I know it's electrical ... so long as its not the TCU itself!!!! lol

Quote:

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Originally Posted by Bigrig

so long as its not the TCU itself!!!! lol

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If you have a manual lock-up switch in it (as I thought you said here) this rules out the TCU as being the problem.

Quote:

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Originally Posted by Bigrig

As I'm sure it was 'measured' with the lockup switch selected

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I wrecked that part of my TCU by feeding 12V into it instead of to the TC solenoid, but the manual switch still makes my TC lock no worries.

Quote:

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Originally Posted by ripper

If you have a manual lock-up switch in it (as I thought you said here) this rules out the TCU as being the problem.



I wrecked that part of my TCU by feeding 12V into it instead of to the TC solenoid, but the manual switch still makes my TC lock no worries.

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Lol - yep, I have a lockup switch mate ... I know it overrides the system as such and if it works it proves the science as it were that the TCU and TC are in fact working etc - was just being a goose!! Mum told me to do what I'm good at in life, and being a clown is about the strength of it!!! lmao

I will suss out that voltage this weekend myself me thinks ... got me interested now ...

Sounds good.

Guys please somebody tell me which wires need to be disconnected when changing to manual
Box fit awesome just need to know which wires go where
Thanks

Near the battery, just under the edge of the air cleaner there are a heap of connectors, I'd start there. They're really annoying to get at in mine because of the LPG conversion. I think they often just get cut off because they're hard to get at, but they need to be unplugged if anyone wants to use the box again.

There are other wires like the throttle position sensor, the full throttle switch, and the TCU, but I think the main ones to remove are the ones into the transmission itself (including it's rev sensor).

On the subject of removing wiring, do you want to sell your TCU?

Hi mate, Could you please spend the time and Introduce yourself to the forum by starting a new thread in the introduction section.

You can find a link to the introduction section in my signature.

Cheers

Todd

Ok all good Guys thanks heaps
Mate talk about the difference in almost everything with a manual gearbox
Wat a change and never goin auto again!



Yes I would sell the tcu although I was hoping to sell it as a complete package with the gearbox, oil lines, oil cooler, and the internal shifter etc
But if u really need it I'm happy to sell it to u
Just let me know how much there worth n well talk business

Cheers